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Veusz - a scientific plotting package

1. to number columns a to b or to number remaining columns See below for examples of this use Dataset names can contain virtually any character even unicode characters If the name contains non alpha numeric characters characters outside of A Z a z and 0 9 then the dataset name should be contained within back tick char acters An example descriptor is length data m speed mps for two datasets with spaces and brackets in their names Instead of specifying the descriptor in the Import dialog the descriptor can be placed in the data file using a descriptor statement on a separate line consisting of descriptor followed by the descriptor Multiple descriptors can be placed in a single file for example here is one section descriptor x y 120255 2 Md 041 20 3 4 0 2 0 1 my next block 10 Reading data descriptor alpha beta gamma 12 3 456 7 8 9 etc Descriptor examples Wom 1 x y two columns are present in the file they will be read in as datasets x and y 2 X y or X y two datasets are in the file Dataset x consists of the first two columns The first column are the values and the second are the symmetric errors y consists of three columns note the comma between and The first column are the values the second positive asymmetric errors and the third negative asymmetric errors Suppose the input file contains 10 043 2 0 1 0 2
2. If you are running your own scripts and do not want to be bothered by these dialogs you can run veusz with the unsafe mode option 28 Chapter 4 Using Veusz from other programs Non Qt Python programs Veusz can be used as a Python module for plotting data There are two ways to use the module 1 with an older path based Veusz commands used in Veusz saved document files or 2 using an object oriented interface With the old style method the user uses a unix path inspired API to navigate the widget tree and add or manipulate widgets With the new style interface the user navigates the tree with attributes of the Root object to access Nodes The new interface is likely to be easier to use unless you are directly translating saved files Older path based interface An example embedding program Veusz needs to be installed into the Python path for this to work use setup py This animates a sin plot then finishes p mport time mport numpy mport veusz embed as veusz pi p construct a Veusz embedded window many of these can be opened at any time g veusz Embedded window title g EnableToolbar construct the plot g To g Add page g To g Add graph g Add xy marker tiehorz MarkerFill__color green this stops intelligent axis extending g Set x autoExtend False g Set x autoExtendZero False zoom out g Zoom 0 8 loop changing the values of th
3. SetDataText SetDataText name val Set the text dataset name with the values given val must be a type that can be converted into a Python list SetDataText mylabel oranges apples pears spam SetToReference SetToReference setting refval 26 Command line interface Set setting to match other setting refval always SetUpdatelnterval SetUpdateInterval interval Tells window to update every interval milliseconds at most The value 0 disables updates until this function is called with a non zero The value 1 tells Veusz to update the window every time the document has changed This will make things slow if repeated changes are made to the document Disabling updates and using the ForceUpdate command will allow the user to control updates directly Note this command is only supported in the embedding interface or veusz_listen SetVerbose Set Verbose v True If v is True then extra information is printed out by commands StartSecondView StartSecond View name window title In the embedding interface this method will open a new Embedding interface onto the same document returning the object This new window provides a second view onto the document It can for instance show a different page to the primary view name is a window title for the new window Note this command is only supported in the embedding interface TagDatasets TagDatasets tag ds1 ds2 Adds the tag
4. Vid 02 Led 2e 2 06 3E0 2 19 0 02 5 Osl i 1 Then x will contain 1 0 3 1 5 0 2 2 19 0 02 y will contain 2 0 1 0 2 2 3 0 02 0 3 5 0 1 0 1 3 x 1 2 y the first column is the data x_1 the second x_2 Subsequent columns are read as y 1 to y n 4 y read each pair of columns as a dataset and its symmetric error calling them y 1 to y n 5 foo read the first column as the foo dataset skip a column and read the third column as its symmetric error CSV files CVS comma separated variable files are often written from other programs such as spreadsheets including Excel and Gnumeric Veusz supports reading from these files In the import dialog choose CSV then choose a filename to import from In the CSV file the user should place the data in either rows or columns Veusz will use a name above a column or to the left of a row to specify what the dataset name should be The user can use new names further down in columns or right in rows to specify a different dataset name Names do not have to be used and Veusz will assign default col and row names if not given You can also specify a prefix which is prepended to each dataset name read from the file To specify symmetric errors for a column put as the dataset name in the next column or row Asymmetric errors can be stated with and in the columns The data type in CSV files are automatically detected unless specified Th
5. italic x Tot Add axis name y To y Set label sin italic x Set direction vertical TOS ft Add xy name xyl To xyl Set MarkerFill color cyan TOR uit Add function name functionl To functionl Set function sin x Set Line color red Toa To Pr 55 To new in python import veusz embed 33 Using Veusz from other programs mbed veusz embed Embedded window title page embed Root Add page note autoAdd False stops graph automatically adding own axes used in saved files graph page Add graph autoadd False x graph Add axis name x x label val italic x y graph Add axis name y y direction val vertical xy graph Add xy xy MarkerFill color val cyan func graph Add function func function val sin x func Line color val red PyQt4 programs There is no direct PyQt4 interface The standard embedding interface should work however Non Python programs Support for non Python programs is available in a limited form External programs may execute the veusz_listen executable or veusz_listen py Python module Veusz will read its input from the standard input and write output to standard output This is a full Python execution environment and supports all the scripting commands mentioned in Commands a Quit command the EnableToolbar and the Zoom factor command
6. second 00 61 U week number of year 00 53 Sunday as first day of week w weekday as decimal number 0 6 W week number of year Monday as first day of week x date representation X time representation y year without century 00 99 and Y year VDVS is a special Veusz addon format which shows seconds and fractions of seconds e g 12 2 Installation Please look at the Installation notes INSTALL for details on installing Veusz The main window You should see the main window when you run Veusz you can just type the veusz command in Unix Introduction File commands Data commands View commands Edit commands V markerspolyyon vsz Veusz 00 File Edit View Insert Data Help Aad ESHA AANE OO LA widgets Pil i iui la le 10 Ekka 450 eeN a Editing Veusz OE A a Type A Plot window B 2 Select LL grapht graph g A x axis widget ae m polygon2 polygon polygoni polygon 7 te none y x 1 a Properties Veusz os a Widget A 5 z X positions stax m a properties lt P M 3 Y positions stary v 8 i Position mode axes 3 z J A E X axis x v n 5 Formatting Veusz 0 o 1 a y Widget formatting Nain Hide Outward ticks on this x azis No position The Veusz window is split into several sections At the top is the menu bar and tool bar These work in the usual way to other applications Sometimes options are disabled greyed out if they do
7. swaps the rows and columns If prefix and or suffix are set they are prepended or appended to imported dataset names If set renames maps imported dataset names to final dataset names after import If the linked parameter is True then the datasets are linked to the imported file and are not saved within a saved document The file format this command accepts is a two dimensional matrix of numbers with the columns separated by spaces or tabs and the rows separated by new lines The X coordinate is taken to be in the direction of the columns Comments are supported use or as are continuation characters Separate datasets are deliminated by using blank lines In addition to the matrix of numbers the various optional parameters this command takes can also be specified in the data file These commands should be given on separate lines before the matrix of numbers They are 1 xrange A B N yrange C D 3 invertrows 4 invertcols 5 transpose ImportFileCSV ImportFileCSV filename readrows False dsprefix names dssuffix linked False encoding utf_8 re This command imports data from a CSV format file Data are read from the file using the dataset names given at the top of the files in columns Please see the reading data section of this manual for more information dsprefix is prepended to each dataset name and dssuffix is added the prefix option is deprecated and also addeds an undersc
8. C negerrcol D linked True False renames This command does a simple import from a FITS file The FITS format is used within the astronomical community to transport binary data For a more powerful FITS interface you can use PyFITS within your scripts The datasetname is the name of the dataset to import the filename is the name of the FITS file to import from The hdu parameter specifies the HDU to import data from numerical or a name If the HDU specified is a primary HDU or image extension then a two dimensional dataset is loaded from the file The optional parameters other than linked are ignored Any WCS information within the HDU are used to provide a suitable xrange and yrange If the HDU is a table then the datacol parameter must be specified and optionally symerrcol poserrcol and negerrcol The dataset is read in from the named column in the table Any errors are read in from the other specified columns Tf linked is True then the dataset is not saved with a saved document but is reread from the data file each time the document is loaded renames if set provides new names for datasets after import ImportString ImportString descriptor data Like ImportFile but loads the data from the specfied string rather than a file This allows data to be easily embedded within a document The data string is usually a multi line Python string Returns A tuple containing a list of the imported datasets and the num
9. Example data file 1 for importing i this is read in with blocks enabled 1 0 1 0 04 ES T2 BA E 24 20 0 11 6 3 35 10 21 Fi 69 40 0 34 81 51 0 11 0 0 698891 867123 0 571271171527 1 1 27652599928 0 293211984296 2 1 80910012902 0 59316037268 A 3 2 49652366924 0 212350438791 v Datasetnames xyz v Help v Ignore text lines Read data in blocks General options Y Link datasets to file Prefix v Character encoding utf_8 v Suffix v Import Close We list the various types of import below Standard text import The default text import operates on simple text files The data are assumed to be in columns separated by whitespace Each column corresponds to dataset or its error bars Each row is an entry in the dataset The way the data are read is goverened by a simple descriptor This can simply be a list of dataset names separated by spaces If no descriptor is given the columns are treated as separate datasets and are given names coll col2 etc Veusz attempts to automatically determine the type of the data When reading in data Veusz treats any whitespace as separating columns The columns do not actually need to be aligned Furthermore a symbol can be placed at the end of a line to mark a continuation Veusz will read the next line as if it were placed at the end of the current line In addition comments and blank lines are ignored unless in block mode Comments start with a or and continue until the end o
10. an external graphs file on the graph or page with size and rotation given The centre can be given in axis coordinates or fractional coordinates line draw a line with optional arrowheads on the graph or page One end can be given in axis coordinates or fractional coordinates contour plot contours of a 2D dataset on the graph Contours are automatically calculated between the minimum and maximum values of the graph or chosen manually The line style of the contours can be chosen individually and the region between contours can be filled with shading or color 2D datasets currently consist of a regular grid of values between minimum and maximum positions in x and y They can be constructed from three 1D datasets of x y and z if they form a regular x y grid image plot a 2D dataset as a colored image Different color schemes can be chosen The scaling between the values and the image can be specified as linear logarithmic square root or square polygon plot x and y points from datasets as a polygon The polygon can be placed directly on the page or within a graph Coordinates are either plotted using the axis or as fractions of the width and height of the containing widget boxplot plot distribution of points in a dataset polar plot polar data or functions This is a non orthogonal plot and is placed directly on the page rather than in a graph ternary plot data of three variables which add up to 100
11. changes the font text is written in to name This may be useful if a symbol is missing from the current font e g font symbol g should produce a gamma You can increase decrease or set the size of the font with size 2 text size 2 text or size 20 text Numbers are in points Various font attributes can be changed for example italic some italic text or use textit or emph bold some bold text or use textbf and underline some underlined text Example text could include Area pi 10 23 cm4 2 or pi bold g Veusz plots these symbols with Qt s unicode support You can also include special characters directly by copying and pasting from a character map application If your current font does not contain these symbols then you may get a box character Introduction Measurements Distances widths and lengths in Veusz can be specified in a number of different ways These include absolute distances specified in physical units e g lcm 0 05m 10mm Sin and 10pt and relative units which are relative to the largest dimension of the page including 5 1 20 0 05 Axis numeric scales The way in which numbers are formatted in axis scales is chosen automatically For standard numerical axes values are shown with the Vg formatting see below For date axes an appropriate date formatting is used so that the interval shown is correct A format can be given for an axis in the a
12. from a text dataset If you wish to leave gaps in a plot the input value nan can be specified in the numeric dataset c fit fit a function to data This plotter is a like the function plotter but allows fitting of the function to data This is achived by clicking on a fit button or using the fit action of the widget The fitter takes a function to fit containing the unknowns e g a x 2 b x c and initial values for the variables here a b and c It then fits the data note that at the moment the fit plotter fits all the data not just the data that can be seen on the graph by minimising the chi squared In order to fit properly the y data or x if fitting as a function of x must have a properly defined preferably symmetric error If there is none Veusz assumes the same fractional error everywhere or symmetrises asym metric errors Note that more work is required in this widget as if a parameter is not well defined by the data the matrix inversion in the fit will fail In addition Veusz does not supply estimates for the errors or the final chi squared in a machine readable way Introduction m If the fitting parameters vary significantly from 1 then it is worth normalizing them by adding in a factor in the fit equation to bring them to of the order of 1 bar a bar chart which plots sets of data as horizontal or vertical bars Multiple datasets are supported In grouped mode the bars are place
13. la le lo Ple 28 88 e ea Editing Veusz 0 y E Name Type ai document E paget page Lo graph graph 0 8 x axis iaa axis Properties Veusz 0 Formatting Veusz 0 Y ele Main gt gt a Hide Left margin 1 7cm v Right margin 01cm v 0 0 2 0 4 0 6 0 8 1 lt gt No position Select the x axis which has been added to the document click on x in the selection window In the properties window you will see a variety of different properties you can modify For instance you can enter a label for the axis by writing Area cm 2 in the box next to label and pressing enter Veusz supports text in LaTeX like form without the dollar signs Other important parameters is the log switch which switches between linear and logarithmic axes and min and max which allow the user to specify the minimum and maximum values on the axes The formatting dialog lets you edit various aspects of the graph appearance For instance the Line tab allows you to edit the line of the axis Click on Line then you can then modify its colour Enter green instead of black and press enter Try making the axis label bold Now you can try plotting a function on the graph If the graph or its children are selected you will then be able to click the function button at the top a red curve on a graph You will see a straight line y x added to the plot If you select function1 you will be able to
14. of the X and Y coordinates of the data xgrid and ygrid are optional lists tuples or arrays which give the coordinates of the edges of the pixels There should be one more item in each array than pixels SetData2DExpression SetData2DExpression name expr linked False Create a 2D dataset based on expressions name is the new dataset name expr is an expression which should return a 2D array linked specifies whether to permanently link the dataset to the expressions SetData2DExpressionXYZ SetData2DExpressionX Y Z name xexpr yexpr zexpr linked False Create a 2D dataset based on three 1D expressions The x y expressions need to evaluate to a grid of x y points with the z expression as the 2D value at that point Currently only linear fixed grids are supported This function is intended to convert calculations or measurements at fixed points into a 2D dataset easily Missing values are filled with NaN SetData2DXYFunc SetData2DX Y Func name xstep ystep expr linked False Wow Construct a 2D dataset using a mathematical expression of x and y The x values are specified as min max step in xstep as a tuple the y values similarly If linked remains as False then a real 2D dataset is created where values can be modified and the data are stored in the saved file SetDataDateTime SetDataDateTime name vals Creates a datetime dataset of name given vals is a list of Python datetime objects
15. per cent This is a non orthogonal plot and is placed directly on the page rather than in a graph Introduction Settings properties and formatting The various settings of the widgets come in a number of types including integers e g 10 floats e g 3 14 dataset names mydata expressions x y text hi there distances see above options horizontal or vertical for axes Veusz performs type checks on these parameters If they are in the wrong format the control to edit the setting will turn red In the command line a TypeError exception is thrown In the GUI the current page is replotted if a setting is changed when enter is pressed or the user moves to another setting The settings are split up into formatting settings controlling the appearance of the plot or properties controlling what is plotted and how it is plotted Default settings including the default font and line style and the default settings for any graph widget can be modified in the Default styles dialog box under the Edit menu Default settings are set on a per document basis but can be saved into a separate file and loaded A default default settings file can be given to use for new documents set in the preferences dialog Text Veusz understands a limited set of LaTeX like formatting for text There are some differences for example 10 23 puts the 2 and 3 into superscript but it is fairly similar You should also leave out
16. style of object interface which makes it easier to construct the widget tree Each widget group of settings or setting is stored as a Node object or its subclass in a tree The root document widget can be accessed with the Root object The dot operator finds children inside other nodes In Veusz some widgets can contain other widgets Root pages graphs grids Widgets contain setting nodes accessed as attributes Widgets can also contain groups of settings again accessed as attributes An example tree for a document not complete might look like this Root X pagel page widget graphl graph widget x axis widget X y axis widget function function widget gridl grid widget graph2 graph widget e kyl xy widget 30 Using Veusz from other programs xData setting yData setting PlotLine setting group width setting x axis widget Nee ay axis widget graph3 graph widget contourl contour widget x axis widget NY axis widget Here the user could access the xData setting node of the xy1 widget using Root pagel graph2 xy1l xData To actually read or modify the value of a setting you should get or set the val property of the setting node The line width could be changed like this graph embed Root pagel graph2 graph xyl PlotLine width val 2pt For instance this constructs a simple x squared plot which changes to x cubed import veus
17. the document is opened The linked parameter is optional If prefix and or suffix are set then the prefix and suffix are added to each dataset name If set renames maps imported dataset names to final dataset names after import 20 Command line interface Returns A tuple containing a list of the imported datasets and the number of conversions which failed for a dataset Changed in version 0 5 A tuple is returned rather than just the number of imported variables ImportFile2D ImportFile2D filename datasets xrange a b yrange c d invertrows True False invertcols True False transpose True False prefix suffix linked False encoding utf8 renames Imports two dimensional data from a file The required arguments are the filename to load data from and the dataset name or a list of names to use filename is a string which contains the filename to use datasets is either a string for a single dataset or a list of strings for multiple datasets The xrange parameter is a tuple which contains the range of the X axis along the two dimensional dataset for example 1 1 represents an inclusive range of 1 to 1 The yrange parameter specifies the range of the Y axis similarly If they are not specified 0 N is the default where N is the number of datapoints along a particular axis invertrows and invertcols if set to True invert the rows and columns respectively after they are read by Veusz transpose
18. the dollar signs Veusz supports superscripts subscripts _ brackets for grouping attributes are and Supported LaTeX symbols include YAA Alpha Beta Chi Delta Epsilon Eta Gamma Mota Kappa Lambda Mu Nu Omega Omicron Phi Pi Psi Rho Sigma Tau Theta Upsilon Xi Zeta alpha approx ast asymp beta bowtie bullet cap chi circ cup dagger dashv ddagger deg delta diamond divide doteq downarrow epsilon equiv eta gamma ge gg in infty int iota kappa lambda Me leftarrow Whd MI models mp mu neq ni nu odot omega omicron ominus oplus oslash otimes parallel perp phi pi pm prec preceq propto psi rhd rho rightarrow sigma sim simeq sqrt sqsubset sqsubseteq sqsupset sqsupseteq star stigma subset isubseteq succ succeq supset isupseteq tau theta times umid unlhd un thd uparrow uplus upsilon vdash vee wedge xi zeta Please request additional characters if they are required and exist in the unicode character set Special symbols can be included directly from a character map Other LaTeX commands are supported breaks a line This can be used for simple tables For example a b c d shows ac over b d The command frac a b shows a vertical fraction a b Also supported are commands to change font The command font name text
19. 5 attribute for the dataset vsz_range which should be set to an array of four values minimum x minimum y maximum x maximum y Dates Date time datasets can be made from a 1D numeric dataset or from a text dataset For the 1D dataset use the number of seconds relative to the start of the year 2009 this is Veusz format or the year 1970 this is Unix format In the import dialog click on the name of the dataset and choose the date option To specify a date format in the HDFS file set the attribute vsz_convert_datetime to either veusz or unix For text datasets dates must be given in the right format selected in the import dialog after clicking on the dataset name As in other file formats by default Veusz uses ISO 8601 format which looks like 2013 12 22T21 08 07 where the date and time parts are optional The T is also optional You can also provide your own format when importing by giving a date expression using Y Y Y Y MM DD hh mm and ss e g Y Y Y Y MM DDITIhh mm ss where vertical bars mark optional parts of the expression To automate this set the attribute vsz_convert_datetime to the format expression or iso to specify ISO format 2D text or CSV format Veusz can import 2D data from standard text or CSV files In this case the data should consist of a matrix of data values with the columns separated by one or more spaces or tabs and the rows on different lines 12 Reading data In addition to the data the fi
20. Quotes can be escaped by prefixing them with a backslash e g A new test If the data are generated from a Python script the repr function provides the text in a suitable form Dates and times are also supported with the syntax dataset date Dates must be in ISO format YYYY MM DD Times are in 24 hour format hh mm ss ss Dates with times are written Y Y Y Y MM DDThh mm ss ss this is a standard ISO format see http www w3 org TR NOTE datetime Dates are stored within Veusz as a number which is the number of seconds since the start of January 1st 2009 Veusz also supports dates and times in the local format though take note that the same file and data may not work on a system in a different location Descriptors A list of datasets or a Descriptor is given in the Import dialog to describe how the data are formatted in the import file The descriptor at its simplest is a space or comma separated list of the names of the datasets to import These are columns in the file nunn Following a dataset name the text or can be given to say that the following column is a positive error bar negative error bar or symmetric error bar for the previous non error bar dataset These symbols should be separated from the dataset name or previous symbol with a space or a comma symbol In addition if multiple numbered columns should be imported the dataset name can be followed by square brackets containing a range in the form a b
21. Use a dataset plugin pluginname name of plugin to use fields dict of input values to plugin datasetnames dict mapping old names to new names of datasets if they are renamed The new name None means dataset is deleted EnableToolbar 18 Command line interface EnableToolbar enable True Enable disable the zooming toolbar in the plotwindow This command is only supported in embedded mode or from veusz_listen Export Export filename color True page 0 dpi 100 antialias True quality 85 backcolor ffffff00 pdfdpi 150 svgtextastext False Export the page given to the filename given The filename must end with the correct extension to get the right sort of output file Currrenly supported extensions are eps pdf ps svg Jpg Jpeg bmp and png If color is True then the output is in colour else greyscale page is the page number of the document to export starting from 0 for the first page A list of pages can be given for multipage formats pdf or ps dpi is the number of dots per inch for bitmap output files antialias antialiases output if True quality is a quality parameter for jpeg output backcolor is the background color for bitmap files which is a name or a RRGGBBAA value red green blue alpha pdfdpi is the dpi to use when exporting EPS or PDF files svgtextastext says whether to export SVG text as text rather than curves FilterDatasets rete rete FilterDatasets filterexpr d
22. Veusz a scientific plotting package Jeremy Sanders Veusz a scientific plotting package Jeremy Sanders Copyright 2015 This document is licensed under the GNU General Public License version 2 or greater Please see the file COPYING for details or see http www gnu org licenses gpl 2 0 html Table of Contents T Introduction O 1 VEU o A Eo A E S EE EE 1 TEMO ci E A EE A AOS EE A ATOL SIATT T 1 MPE E ee eae s 1 Settings properties and formatting sess susesi ek es beteg ben wade ack ET a E eE 4 A A 4 Me easurements sisses irnir e aa Re boas ois aa s E TS EEEn ose dhecduaug seb NTE sees seugas etna desea ne 5 AXIS TUMETIC sales seisot erin e EE e ies 5 Installawon srogo O SO 5 The Main WIndows e enna aes He A A A EEEE EE E r e E 5 My first O S s 6 2 Reading data ii A E AEE EEE EE E EE EEEE a 9 Standard text IMPort ti rr e A E E ETE E E E EE E a D E EEES 9 Data types in text import iie a or O E EE E E E E EEE EE e eS 10 DESCTIPLOLS odie ti Er E Eaa a dae ii Ee EEES 10 CSV GIES shareit iao Ses etched EE nE Mat desde EE TTE E E tes EE EEE EE E EAEE E 11 HDES files niero tdo a a a T a E a E a aE 11 Error Dats eves A A A A A ss Sv E 12 MC at A E T 12 2D data TAN SES ria 12 Dates eate erme ae aa E aE E EE E T TE A E E E E E EA O E S 12 2D text or CSV format isoa ereo T iE nE EEEE sue EEE E SE EEIE ESE EEEE EE E 12 ETES MES E E E EE E T T 13 Reading other data formats seserian esn e cece eds EEE EE TEE E d
23. and poserr and the getative and positive asymmetric errors The data can be given as lists or numpys SetDataExpression SetDataExpression name val symerr None negerr None poserr None linked False parametric None Create a new dataset based on the expressions given The expressions are Python syntax expressions based on existing datasets If linked is True the dataset will change as the datasets in the expressions change Parametric can be set to a tuple of minval maxval numitems t in the expression will iterate from minval to maxval in numitems values SetDataRange SetDataRange name numsteps val symerr None negerr None poserr None linked False Set dataset to be a range of values with numsteps steps val is tuple made up of minimum value maximum value symerr negerr and poserr are optional tuples for the error bars If linked is True the dataset can be saved in a document as a SetDataRange otherwise it is expanded to the values which would make it up 25 Command line interface SetData2D SetData2D name val xrange A B yrange C D xgrid 1 2 3 ygrid 4 5 6 Creates a two dimensional dataset with the name given val is either a two dimensional numpy array or is a list of lists with each list in the list representing a row Do not give xrange if xgrid is set and do not give yrange if ygrid is set and vice versa xrange and yrange are optional tuples giving the inclusive range
24. arated items in a string If mode is appendalways the custom value is appended to the end of the list even if there is one with the same name If mode is replace it replaces any existing definition in the same place in the list or is appended otherwise If mode is append then an existing definition is deleted and the new one appended to the end AddIimportPath AddImportPath directory Add a directory to the list of directories to try to import data from CloneWidget Clone Widget widget newparent newname None Clone the widget given placing the copy in newparent and the name given newname is an optional new name to give 1t Returns new widget path Close Close Closes the plotwindow This is only supported in embedded mode CreateHistogram CreateHistogram inexpr outbinsds outvalsds binparams None binmanual None method counts cumula tive none errors False Histogram an input expression inexpr is input expression outbinds is the name of the dataset to create giving bin positions outvalsds is name of dataset for bin values binparams is None or numbins minval maxval islogbins binmanual is None or a list of bin values method is counts density or fractions cumulative is to calculate cumu lative distributions which is none smalltolarge or largetosmall errors is to calculate Poisson error bars DatasetPlugin DatasetPlugin pluginname fields datasetnames gt
25. atasets For the datasets which are error bars use a name which is the same as the main dataset but with the suffix or for symmetric postive or negative error bars respectively The second method is to use a 2D dataset with two or three columns for symmetric or asymmetric error bars respectively Click on the dataset in the dialog and choose the option to import as a 1D dataset This second method can also be enabled by adding an HDF5 attribute vsz_twod_as_oned set to a non zero value for the dataset Slices As Veusz only supports 1D and 2D datasets you may wish to reduce the dimensions of a dataset before importing by slicing You can also give a slice to import a subset of a dataset When importing in the slice column you can give a slice expression This should have the same number of entries as the dataset has dimensions separated by commas An entry can be a single number to select a particular row or column Alternatively it could be an expression like a b c or a b where a is the starting index b is one beyond the stopping index and optionally c is the step size A slice can also be specified by providing an HDF5 attribute vsz_slice for the dataset 2D data ranges 2D data have an associated X and Y range By default the number of pixels of the image are used to give this range A range can be specified by clicking on the dataset and entering a minimum and maximum X and Y coordinates Alternatively provide the HDF
26. atasets prefix suffix invert False replaceblanks False Filter a list of datasets given Creates new datasets for each with prefix and suffix added to input dataset names filterexpr is an input numpy eexpression for filtering the datasets If invert is set the filter condition is inverted If replaceblanks is set filtered values are not removed but replaced with a blank or NaN value This command only works on 1D numeric date or text datasets ForceUpdate ForceUpdate Force the window to be updated to reflect the current state of the document Often used when periodic updates have been disabled see SetUpdateInterval This command is only supported in embedded mode or from veusz_listen Get Get settingpath Returns The value of the setting given by the path gt gt gt Get pagel graph1 x min Auto GetChildren GetChildren where Returns The names of the widgets which are children of the path given GetClick GetClick 19 Command line interface Waits for the user to click on a graph and returns the position of the click on appropriate axes Command only works in embedded mode Returns A list containing tuples of the form axispath val for each axis for which the click was in range The value is the value on the axis for the click GetData GetData name Returns For a 1D dataset a tuple containing the dataset with the name given The value is data symerr negerr po
27. ber of conversions which failed for a dataset Changed in version 0 5 A tuple is returned rather than just the number of imported variables ImportString A R y py 090 1 2 2 5 3 10 TO ImportString2D ImportString2D datasets string Imports a two dimensional dataset from the string given This is similar to the ImportFile2D command with the same dataset format within the string This command however does not currently take any optional parameters The various controlling parameters can be set within the string See the ImportFile2D section for details IsClosed IsClosed Returns a boolean value telling the caller whether the plotting window has been closed Note this command is only supported in the embedding interface 23 Command line interface List List where List the widgets which are contained within the widget with the path given the type of widgets and a brief description Load Load filename vsz Loads the veusz script file given The script file can be any Python code The code is executed using the Veusz interpreter Note this command is only supported at the command line and not in a script Scripts may use the python execfile function instead MoveToPage MoveToPage pagenum Updates window to show the page number given of the document Note this command is only supported in the embedding interface or veusz_listen ReloadData ReloadData Reload any datasets which have b
28. d side by side for each dataset In stacked mode the bars are placed on top of each other in the appropriate direction according to the sign of the dataset Bars are placed on coordinates given or in integer values from upward if none are given Error bars are plotted for each of the datasets Different fill styles can be given for each dataset given A separate key value can be given for each dataset key a box which describes the data plotted If a key is added to a plot the key looks for key settings of the other data plotted within a graph If there any it builds up a box containing the symbol and line for the plotter and the text in the key setting of the widget This allows a key to be very easily added to a plot The key may be placed in any of the corners of the plot in the centre or manually placed Depending on the ordering of the widgets the key will be placed behind or on top of the widget The key can be filled and sur rounded by a box or not filled or surrounded label a text label places on a graph The alignment can be adjusted and the font changed The position of the label can be specified in fractional terms of the current graph or using axis coordinates rect ellipse these draw a rectangle or ellipse respectively of size and rotation given These widgets can be placed directly on the page or on a graph The centre can be given in axis coordinates or fractional coordinates imagefile draw
29. dataset plugins exist which make certain operations on datasets much more convenient See the Data Operations menu for a list of the default plugins The user can easily create new plugins See http barmag net veusz wiki DatasetPlugins for details Capturing data In addition to the standard data import data can be captured as it is created from an external program a network socket or a file or named pipe When capturing from a file the behaviour is like the Unix tail f command where new lines written to the file are captured To use the capturing facility the data must be written in the simple line based standard Veusz text format Data are whitespace separated with one value per dataset given on a single line To capture data use the dialog box Data _ Capture A list of datasets should be given This is the standard descriptor format Choose the source of the data which is either a a filename or named pipe a network socket to connect to or a command line for an external program Capturing ends if the source of the data runs out for external programs or network sockets or the finish button is clicked It can optionally end after a certain number of data lines or when a time period has expired Normally the data are updated in Veusz when the capturing is finished There is an option to update the document at intervals which is useful for monitoring A plot using the variables will update when the data are updated Click the Capture but
30. dgettyp get Veusz type of widget Methods are below def WalkWidgets self widgettype None Generator to walk widget tree and get widgets below this WidgetNode of type given widgettype is a Veusz widget type name or None to get all widgets def Add self widgettype args args_opt Add a widget of the type given returning the Node instance def Rename self newname Renames widget to name given Existing Nodes corresponding to children are no longer valid 32 Using Veusz from other programs def Action self action Applies action on widget def Remove self Removes a widget and its children Existing Nodes corresponding to children are no longer valid Note that Nodes are temporary objects which are created on the fly A real widget in Veusz can have several different WidgetNode objects The operators and can test whether a Node points to the same widget setting or setting group Here is an example to set all functions in the document to be x 2 for n in Root WalkWidgets widgettype function n function val x 2 Translating old to new style Here is an example how you might translate the old to new style interface this is taken from the sin vsz example old from saved document file Add page name pagel To pagel Add graph name graph1 autoadd False To graphl Add axis name x To x Set label
31. e data type can be given in brackets after the column name e g name text where the data type is date numeric or text Explicit data types are needed if the data look like a different data type e g a text item of 1 23 The date format in CSV files can be specified in the import dialog box see the examples given In addition CSV files support numbers in European format e g 2 34 rather than 2 34 depending on the setting in the dialog box HDF5 files HDES is a flexible data format Datasets and tables can be stored in a hierarchical arrangements of groups within a file Veusz supports reading 1D numeric text date time or 2D numeric data from HDF files The h5py Python module must be installed to use HDFS files included in binary releases 11 Reading data In the import dialog box choose which individual datasets to import or selecting a group to import all the datasets within the group If selecting a group datasets in the group incompatible with Veusz are ignored A name can be provided for each dataset imported by entering one under Import as If one is not given the dataset or column name is used The name can also be specified by setting the HDF5 dataset attribute vsz_name to the name Note that for compound datasets tables vs z__ attributes for columns are given by appending the suffix _column name to the attribute Error bars Error bars are supported in two ways The first way is to combine 1D d
32. e is no actual plotter widget which can be added but several types of plotters listed below Plotters typically take an axis as a setting which is the axis used to plot the data on the graph default x and y a function a plotter which plots a function on the graph Functions can be functions of x or y parametric functions are not done yet and are defined in Python expression syntax which is very close to most other languages For example 3 x 2 2 x 4 A number of functions are available e g sin cos tan exp log Technically Veusz imports the numpy package when evaluating so numpy functions are available As well as the function setting also settable is the line type to plot the function and the number of steps to evaluate the function when plotting Filling is supported above below left right of the function b xy a plotter which plots scatter line or stepped plots This versatile plotter takes an x and y dataset and plots optional points in a chosen marker and colour connecting them with optional lines and plotting optional error bars An xy plotter can also plot a stepped line allowing histograms to be plotted note that it doesn t yet do the binning of the data The settings for the xy widget are the various attibutes for the points line and error bars the datasets to plot and the axes to plot on The xy plotter can plot a label next to each dataset which is either the same for each point or taken
33. e x and y datasets for i in range 10 x numpy arange 0 1 2 7 i 2 0 05 y numpy sin x g SetData x x g SetData y y wait to animate the graph time sleep 2 29 Using Veusz from other programs let the user s the final result print Waiting for 10 seconds time sleep 10 print Done close the window this is not strictly necessary g Close The embed interface has the methods listed in the command line interface listed in the Veusz manual http home gna org veusz docs manual html Multiple Windows are supported by creating more than one Embedded object Other useful methods include e WaitForClose wait until window has closed e GetClick return a list of axis value tuples where the user clicks on a graph e ResizeWndow width height resize window to be width x height pixels e SetUpdatelnterval interval set update interval in ms or 0 to disable e MoveToPage page display page given starting from 1 e IsClosed has the page been closed e Zoom factor set zoom level float or page width height e Close close window e SetAntiAliasing enable enable or disable antialiasing e EnableToolbar enable True enable plot toolbar e StartSecondView name Veusz start a second view onto the document of the current Embedded ob ject Returns a new Embedded object New style object interface In versions of Veusz gt 1 8 is a new
34. ec Ea 13 Manipulating dataset ico ri a a A eas sada E E E E A 14 Using dataset plUZInS oiaro niire a E EEE E E T cloves lates ee eee Rt EESTI eas 14 Using expressions to create new datasets 0 0 0 0 cece cece cece eee eeca ceca eeaeeeae eens eeneeeeeeeeeeeeeeeeeeaees 14 Linking datasets to expressions 2 1 0 0 eee cece cece cece cence ee ceneceeeceeeeeeseeeeaeeeaeeea esas eeas eeu eeaeeeenees 15 Splittin S data sosic5 costes sees sy a ses Pata aes Betta bes E vans wate Sense E E yeaa pss oe E SENG eae 15 Defining new constants Or functions 2 2 0 0 ee eee ee ce ee cc ee ce eeceeeceeeeaeeeaeeeaeeea sean ecu eeneeneeeneees 15 Dataset O 16 Captiiring data nene a 16 3 Command line Interface polio E E EE Ea E ba sate stetal as 17 Introduction sin es Ek ia EE EAE Os AL te Sea oe A ee 17 A des ots tas sctnd estes seeag Seeseea de svosss abc osa ees sou cd iseota css peves cabwedsausnes sues seeaeeds septs age eeds 17 Aci ai as le eels 17 Add sitiar batida riera a bis catia son E E oeaee a ode sas batted ice bate ean ira roads 17 AOA CUSIOM ui IAS EA A ADO fess Wes E IIA eR is 17 A eaesiacs tees srera ERIT ATORE voeecshews sapelesasebegeed asugesbotaeghoee sees sapeteaeees 18 Clone Wid S6b cosets ietied cin aee Ne EE dais 18 RR en Mears savbetaaacedetas es pat dates tatty seu be we eeatte saber deter datas asbeweabatnsea va ET 18 Create SOTA A ces toes ea eed eet jos Ses EEEE E sees etes dees ENE EES eek 18 DatasetPlgins se oi suede savas s
35. edit the functional form plotted and the style of its line Change the function to x 2 x squared We will now try plotting data on the graph Go to your favourite text editor and save the following data as test dat 1 0 1 0 12 1 1 0 1 2 05 0 12 0 14 4 08 0 12 2 98 0 08 0 L 2 9 0 11 4 02 0 04 0 1 153 1 0 The first three columns are the x data to plot plus its asymmetric errors The final two columns are the y data plus its symmetric errors In Veusz go to the Data menu and select Import Type the filename into the filename box or use the Browse button to search for the file You will see a preview of the data pop up in the box below Enter x y into the descriptors edit box note that commas and spaces in the descriptor are almost interchangeable in Veusz 1 6 or newer This describes the format of the data which describes dataset x plus its asymmetric errors and Woo Woo y with its symmetric errors If you now click Import you will see it has imported datasets x and y To plot the data you should now click on graph in the tree window You are now able to click on the xy button which looks like points plotted on a graph You will see your data plotted on the graph Veusz plots datasets x and Woo y by default but you can change these in the properties of the xy plotter Introduction You are able to choose from a variety of markers to plot You can remove the plot line by choosing t
36. een linked to files Returns A tuple containing a list of the imported datasets and the number of conversions which failed for a dataset Rename Remove widgetpath newname Rename the widget at the path given to a new name This command does not move widgets See To for a description of the path syntax can be used to select the current widget Remove Remove widgetpath Remove the widget selected using the path See To for a description of the path syntax ResizeWindow Resize Window width height Resizes window to be width by height pixels Note this command is only supported in the embedding interface or veusz_listen 24 Command line interface Save Save filename vsz Save the current document under the filename given Set Set settingpath val Set the setting given by the path to the value given If the type of val is incorrect an Invalid Type exception is thrown The path to the setting is the optional path to the widget the setting is contained within an optional subsetting specifier and the setting itself Set pagel graph1 x min 10 SetAntiAliasing SetAntiAliasing on Enable or disable anti aliasing in the plot window replotting the image SetData SetData name val symerr None negerr None poserr None Set the dataset name with the values given If None is given for an item it will be left blank val is the actual data symerr are the symmetric errors negerr
37. efined in parent widgets shared with other graphs More than one graph can be placed within in a page The margins can be adjusted so that they lie within or besides each other Introduction 4 grid containing one or more graphs A grid plots graphs in a gridlike fashion You can specify the number of rows and columns and the plots are automatically replotted in the chosen arrangement A grid can contain graphs or axes If an axis is placed in a grid it can be shared by the graphs in the grid 5 axis giving the scale for plotting data An axis translates the coordinates of the data to the screen An axis can be linear or logarithmic it can have fixed endpoints or can automatically get them from the plotted data It also has settings for the axis labels and lines tick labels and major and minor tick marks An axis may be horizontal or vertical and can appear anywhere on its parent graph or grid If an axis appears within a grid then it can be shared by all the graphs which are contained within the grid The axis broken widget is an axis sub type It is an axis type where there are jumps in the scale of the axis The axis function widget allows the user to create an axis where the values are scaled by a monotonic function al lowing non linear and non logarithmic axis scales The widget can also be linked to a different axis via the function 6 plotters types of widgets which plot data or add other things on a graph Ther
38. ent e g pagel graph1 functionl type type of node widget settinggroup or setting name name of this node e g graphl children a generator to return all the child Nodes of this Node e g for c in Root children print c path children_widgets generator to return child widget Nodes of this Node children_settinggroups generator for child setting groups of this Node children_settings a generator to get the child settings childnames return a list of the names of the children of this Node c Cc hildnames_widgets return a list of the names of the child widgets hildnames_settinggroups return a list of the names of the setting groups hildnames_settings return a list of the names of the settings parent return the Node corresponding to the parent widget of this Node _ getattr get a child Node with name given e g Root pagel getitem__ get a child Node with name given e g Root pagel def fromPath self path Returns a new Node corresponding to the path given e g pagel graph1 class SettingNode Node A node which corresponds to a setting Extra properties val get or set the setting value corresponding to this value e g Root pagel graphl leftMargin val 2cm class SettingGroupNode Node A node corresponding to a setting group No extra properties class WidgetNode Node A node corresponding to a widget property wi
39. f the line The special value nan can be used to specify a break in a dataset Reading data If the option to read data in blocks is enabled Veusz treats blank lines or lines starting with the word no as block separators For each dataset in the descriptor separate datasets are created for each block using a numeric suffix giving the block number e g _1 _2 Data types in text import Veusz supports reading in several types of data The type of data can be added in round brackets after the name in the descriptor Veusz will try to guess the type of data based on the first value so you should specify it if there is any form of ambiguity e g is 3 text or a number Supported types are numbers use numeric in brackets and text use text in brackets An example descriptor would be x numeric y numeric label text for an x dataset followed by its symmetric errors a y dataset followed by two columns of asymmetric errors and a final column of text for the label dataset A text column does not need quotation unless it contains space characters or escape characters However make sure you deselect the ignore text option in the import dialog This ignores lines of text to ease the import of data from other applications Quotation marks are recommended around text if you wish to avoid ambiguity Text is quoted according to the Python rules for text Double or single quotation marks can be used e g A test A second test
40. he Plot Line subsetting and clicking on the hide option You can change the colour of the marker by going to the Marker Fill subsetting and entering a new colour e g red into the colour property Chapter 2 Reading data Currently Veusz supports reading data from files with text CSV HDF5 FITS 2D text or CSV QDP binary and NPY NPZ formats Use the Data _ Import dialog to read data or the importing commands in the API can be used In addition the user can load or write import plugins in Python which load data into Veusz in an arbitrary format At the moment QDP binary and NPY NPZ files are supported with this method The HDF5 file format is the most sophisticated and is recommended for complex datasets By default data are linked to the file imported from This means that the data are not stored in the Veusz saved file and are reloaded from the original data file when opening In addition the user can use the Data _ Reload menu option to reload data from linked files Unselect the linked option when importing to remove the association with the data file and to store the data in the Veusz saved document Note that a prefix and suffix can be given when importing These are added to the front or back of each dataset name imported They are convenient for grouping data together Y Import data Veusz OOA 6 Filename jss codelveuszlexamples example_impori_1 dat w Browse Standard CSY FITS 2D File preview
41. idget component given the action name Actions perform certain automated routines These include fit on a fit widget and zeroMargins on grids Add Add widgettype name nameforwidget autoadd True optionalargs The Add command adds a graph into the current widget See the To command to change the current position non n The first argument is the type of widget to add These include graph page axis xy and grid name is the name of the new widget if not given it will be generated from the type of the widget plus a number The autoadd parameter if set constructs the default sub widgets this widget has for example axes in a graph Optionally default values for the graph settings may be given for example Add axis name y direction vertical Subsettings may be set by using double underscores for example Add xy MarkerFill__color red ErrorBarLine__hide True Returns Name of widget added AddCustom 17 Command line interface AddCustom type name value Add a custom definition for evaluation of expressions This can define a constant can be in terms of other constants a function of 1 or more variables or a function imported from an external python module ctype is constant function or import name is name of constant or function x y or module name val is definition for constant or function both are _strings_ or is a list of symbols for a module comma sep
42. ing give the coordinates of the edges of the pixels in the y axis If the values are increasing the lowest coordinate value is at the bottom row If they instead decrease it is at the top 5 xcent A B C rather than give a total range or pixel edges give the centres of the pixels There should be the same number of values as pixels in the image Do not give xrange or xedge if this is given The order of the values specify whether the pixels are left to right or right to left 6 ycent A B C rather than give a total range or pixel edges give the centres of the pixels The value order specifies whether the pixels are bottom to top or top to bottom 7 invertrows invert the rows after reading the data 8 invertcols invert the columns after reading the data 9 transpose swap rows and columns after importing data 10 gridatedge the first row and leftmost column give the positions of the centres of the pixels This is also an option in the import dialog The values should be increasing or decreasing FITS files 1D or 2D data can be read from FITS files 1D data with optional errors bars can be read from table extensions and 2D data from image or primary extensions Note that pyfits or astropy must be installed to get FITS support To read 1D data choose a tabular HDU for to import from enter the name to give the imported data and choose the columns to assign to the data Multiple sets of data can be read by repeatedly i
43. ion changes the dataset changes with it like in a spreadsheet Splitting data Data can also be chopped in this method for example using the expression x 10 20 which makes a dataset based on the 11th to 20th item in the x dataset the ranges are Python syntax and are zero based Negative indices count backwards from the end of the dataset Data can be skipped using expressions such as data 2 which skips every other element Defining new constants or functions User defined constants or functions can be defined in the Custom definitions dialog box under the edit menu Func tions can also be imported from external python modules 15 Reading data gt x Custom definitions OOA Definitions Alist of custom functions constants or symbols imported from external Python modules These can be used when plotting functions creating new datasets and fitting data Definitions are saved with the document and evaluated from the top down in order Afile with default custom settings can be specified in the preferences dialog Type Name Definition constant mypi 3 14159 function great x cos mypi Move up Move down Add Remove Save Load Recent Close Custom definitions are defined on a per document basis but can be saved or loaded into a file A default custom definitions file can be set in the preferences dialog box Dataset plugins In addition to creating datasets based on expressions a variety of
44. is window is not shown by default but can be enabled in the View menu The console is a Veusz and Python command line console To read about the commands available see Commands As this is a Python console you can enter mathematical expressions e g 1 2 0 cos pi 4 here and they will be evaluated when you press Enter The usual special functions and the operators are supported You can also assign results to variables e g a 1 2 for use later The console also supports command history like many Unix shells Press the up and down cursor keys to browse through the history Command line completion is not available yet There also exists a dataset browsing window by default to the right of the screen This window allows you to view the datasets currently loaded their dimensions and type Hovering a mouse over the size of the dataset will give you a preview of the data My first plot After opening Veusz on the left of the main window you will see a Document containing a Page which contains a Graph with its axes The Graph is selected in the selection window The toolbar above adds a new widget to the Introduction selected widget If a widget cannot be added to a selected widget it is disabled On opening a new document Veusz automatically adds a new Page and Graph with axes to the document You will see something like this o gt 3 Y Untitled Veusz File Edit View Insert Data Help HEB4A BANLE CAREA Dl i im
45. le can contain lines at the top which affect the import Such specifiers are used for example to change the coordinates of the pixels in the file By default the first pixels coordinates is between 0 and 1 with the centre at 0 5 Subsequent pixels are 1 greater Note that the lowest coordinate pixel is the bottom left value in the table of imported values When using specifiers in CSV files put the different parts separated by spaces in separate columns Below are listed the specifiers 1 xrange A B make the 2D dataset span the coordinate range A to B in the x axis where A and B are numbers Note that the range is inclusive so a 1 pixel wide image with A 0 and B 1 would have the pixel centre at 0 5 The pixels are assumed to have the same spacing Do not use this as the same time as the xedge or xcent options 2 yrange A B make the 2D dataset span the coordinate range A to B in the y axis where A and B are numbers 3 xedge A B C rather than assume the pixels have the same spacing give the coordinates of the edges of the pixels in the x axis The numbers should be space separated and there should be one more number than pixels Do not give xrange or xcent if this is given If the values are increasing the lowest coordinate value is at the left of the dataset otherwise if they are decreasing it is on the right unless the rows columns are inverted or transposed 4 yedge A B C rather than assume the pixels have the same spac
46. listed above Only one window is supported at once but many veusz_listen programs may be started veusz_listen may be used from the shell command line by doing something like veusz_listen lt in vsz where in vsz contains To Add page To Add graph SetData x arange 20 SetData y arange 20 2 Add xy Zoom 0 5 Export foo eps Quit A program may interface with Veusz in this way by using the popen C Unix function which allows a program to be started having control of its standard input and output Veusz can then be controlled by writing commands to an input pipe C C and Fortran A callable library interface to Veusz is on my todo list for C C and Fortran Please tell me if you would be interested in this option 34
47. modified in the Data Editor dialog box This dialog box can also be used to create new datasets from scratch by typing them in The Data Create dialog box is used to new datasets as a numerical sequence parametrically or based on other datasets given expressions If you want to plot a function of a dataset you often do not have to create a new dataset Veusz allows to enter expressions directly in many places Using dataset plugins Dataset plugins can be used to perform arbitrary manipulation of datasets Veusz includes several plugins for mathe matical operation of data and other dataset manipulations such as concatenation or splitting If you wish to write your own plugins look at http barmag net veusz wiki DatasetPlugins Using expressions to create new datasets For instance if the user has already imported dataset d then they can create d2 which consists of d 2 Expressions are in Python numpy syntax and can include the usual mathematical functions 14 Reading data Y Create dataset Veusz VOW Name newdataset v Method of creating dataset Value or range Number of steps 100 Y Parametric as an expression oft t 0 wl to 1 v in 100 v steps inclusive Expression using existing datasets Dataset values or expressions Enter expressions as a function of other datasets Append suffixes _data _serr _herr and _perrto access different parts of datasets If a dataset name contains punctuation or spaces surround
48. mporting For 2D data choose an image HDU Enter the name of the dataset The data are imported with pixel coordinates by default i e the pixels are numbered with integers Other modes can be selected under Image WCS mode These include fractional where the pixels are numbered between 0 and 1 Pixel WCS assigns the pixel coordinate calculated relative to the CRPIX1 2 header keywords Linear WCS uses linear coordinates where the Pixel WCS coordinates are multiplied by the respective CDELT1 2 values and added to the CRVAL1 2 values Reading other data formats As mentioned above a user may write some Python code to read a data file or set of data files To write a plugin which is incorportated into Veusz see http barmag net veusz wiki ImportPlugins 13 Reading data You can also include Python code in an input file to read data which we describe here Suppose an input file in dat contains the following data Ss 0 DN E Pwo PB N Of course this data could be read using the ImportFile command However you could also read it with the following Veusz script which could be saved to a file and loaded with execfile or Load The script also places symmetric errors of 0 1 on the x dataset xo 11 y for line in open in dat parts float i for i in line split x append parts 0 y append parts 1 SetData x x symerr 0 1 SetData y y Manipulating datasets Imported datasets can easily be
49. not make sense to be used If you hold your mouse over a button for a few seconds you will usually get an explanation for what it does called a tool tip Below the main toolbar is a second toolbar for constructing the graph by adding widgets on the left and some editing buttons The add widget buttons add the request widget to the currently selected widget in the selection window The widgets are arranged in a tree like structure Below these toolbars and to the right is the plot window This is where the current page of the current document is shown You can adjust the size of the plot on the screen the zoom factor using the View menu or the zoom tool bar button the magnifying glass Initially you will not see a plot in the plot window but you will see the Veusz logo At the moment you cannot do much else with the window In the future you will be able to click on items in the plot to modify them To the left of the plot window is the selection window and the properties and formatting windows The properties window lets you edit various aspects of the selected widget such as the minimum and maximum values on an axis Changing these values should update the plot The formatting lets you modify the appearance of the selected widget There are a series of tabs for choosing what aspect to modify The various windows can be dragged from the main window to float by themselves on the screen To the bottom of the window is the console Th
50. onds since 2009 01 01 if this is set to unix this is the number of seconds since 1970 01 01 For a text dataset this should give the format of the date time e g YY Y Y MM DDITIhh mm ss or iso for iso format renames is a dict mapping old to new dataset names to be renamed after importing linked specifies that the dataset 1s linked to the file Attributes can be used in datasets to override defaults vsz_name set to override name for dataset in veusz vsz_slice slice on importing use format Start stop step vsz_range should be 4 item array to specify x and y ranges minx miny maxx maxy vsz_twod_as_oned treat 2d dataset as 1d dataset with errors vsz_convert_datetime treat as date time set to one of the values above For compound datasets these attributes can be given on a per column basis using attribute names vsz_attributename_columnname Returns list of imported datasets ImportFilePlugin ImportFilePlugin pluginname filename pluginargs linked False encoding utf_8 prefix suffix renames Import data from file using import plugin pluginname The arguments to the plugin are given plus optionally a text encoding and prefix and suffix to prepend or append to dataset names renames if set provides new names for datasets after import 22 Command line interface ImportFITSFile ImportFITSFile datasetname filename hdu datacol A symerrcol B poserrcol
51. ore to the dataset name linked specifies whether the data will be linked to the file renames if set provides new names for datasets after import 21 Command line interface ImportFileHDF5 ImportFileHDF5 filename items namemap slices twodranges twod_as_oned set convert_datetime prefix suffix renames linked False Import data from a HDF file items is a list of groups and datasets which can be imported If a group is imported all child datasets are imported namemap maps an input dataset to a veusz dataset name Special suffixes can be used on the veusz dataset name to indicate that the dataset should be imported specially foo import as ve error for dataset foo foo import as ve error for dataset foo foo import as symmetric error for dataset foo slices is an optional dict specifying slices to be selected when importing For each dataset to be sliced provide a tuple of values one for each dimension The values should be a single integer to select that index or a tuple start stop step where the entries are integers or None twodranges is an optional dict giving data ranges for 2d datasets It maps names to minx miny maxx maxy twod_as_oned optional set containing 2d datasets to attempt to read as 1d convert_datetime should be a dict mapping hdf name to specify date time importing For a 1d numeric dataset if this is set to veusz this is the number of sec
52. preSSiO sortir e eE EE a a Lau cane EE a N E Ee 26 SetData2DEXpressIONA AL a a O eii 26 ABAD soaneve ne eemess de naeas RE A Sea ous pe Suede ga vad E Berges neweness E EEEN 26 Set DataDate Time nia AS RU CRS ee inde il 26 SetData E tee cua dave Pee stan shea AN sadedadagebsnen se EEE 26 SetlOReeren Ce sh skh yh el ee Bite a E TS A Shean tee ye 26 SetUpdatelnterval econo ato a eto toemesey coeebe E AE EE R EES geet 27 SetVerDO Se n a AS RA osa 27 StartSecond View pene an a I dives bas e E aa e S e picada 27 Tag Datasets earen ennei aa E EEA E AEE A R EAA pE AERE EA 27 O NOS 27 QUibasii a ode As a i al Se Read as ee ees 27 WiaitBor loses case droit is ti a E hes Mveuten syed acddeh een sensdh ogee aes iaa 27 LOOM sits yh E eee oh oan A T A LI dua RE 28 SECUTILY nfs wes tes A tierno repito pro E E AE AEE ET 28 4 Using Veusz from other programs tir ds aes ee ee aa ed 29 Non Ot Python programs 2 00 4 0y secede intel rare neat ueel a ns nese sueedy chance Seo E E donb dae 29 Older path based interlace su kos cys eeekes seve Me E e ict aioe he 29 NEVA ER e aay sco odes oeeswae sage tec guisph wen vsesh wed geet wotes setae E E se nyse eps EOE ese I EEES 30 Translating old to mew style ri ii 33 Py QU programs aiee sea tebee wot haz awe saa seeeta ced eea den sewekd ote deh daen es ostace debbadondeuegd E agaeg der E aS 34 Non Python proeraims 2 08 A ee Sere ieee ea cee 34 C Cand FOrtr ant A A de 34 iv Chapter 1 Introduc
53. serr with each a numpy array of the same size or None data are the values of the dataset symerr are the symmetric errors if set negerr and poserr and negative and positive asymmetric errors if set If a text dataset return a list of text elements If the dataset is a date time dataset return a list of Python datetime objects If the dataset is a 2D dataset return the tuple data rangex rangey where data is a 2D numpy array and rangex y are tuples giving the range of the x and y coordinates of the data data GetData x SetData x data 0 0 1 data 1 GetDataType GetDataType name Get type of dataset with name given Returns 1d for a 1d dataset 2d for a 2d dataset text for a text dataset and datetime for a datetime dataset GetDatasets GetDatasets Returns The names of the datasets in the current document GPL GPLO Print out the GNU Public Licence which Veusz is licenced under ImportFile ImportFile filename descriptor linked False prefix suffix encoding utf_8 renames Imports data from a file The arguments are the filename to load data from and the descriptor The format of the descriptor is a list of variable names representing the columns of the data For more information see Descriptors If the linked parameter is set to True if the document is saved the data imported will not be saved with the document but will be reread from the filename given the next time
54. t and its parent The widgets have a number of different settings which modify their behaviour These settings are divided into properties which affect what is plotted and how it is plotted These would include the dataset being plotted or whether an axis is logarithmic There are also formatting settings including the font to be used and the line thickness In addition they have actions which perform some sort of activity on the widget or its children like fit for a fit widget As an aside using the scripting interface widgets are specified with a path like a file in Unix or Windows These can be relative to the current widget do not start with a slash or absolute do not start with a slash Examples of paths include page1 graph1 x x and The widget types include 1 document representing a complete document A document can contain pages In addition it contains a setting giving the page size for the document 2 page representing a page in a document One or more graphs can be placed on a page or a grid 3 graph defining an actual graph A graph can be placed on a page or within a grid Contained within the graph are its axes and plotters A graph can be given a background fill and a border if required It also has a margin which specifies how far away from the edge of its parent widget to plot the body of the graph A graph can contain several axes at any position on the plot In addition a graph can use axes d
55. the name with backticks Value olddataset 10 5 v Symmetric error olddataset_data 0 1 y Positive error v Negative error v Y Link this dataset to these expressions Create Close Expressions for error bars can also be given By appending _data _serr _perr or _nerr to the name of the dataset in the expression the user can base their expression on particular parts of the given dataset the main data symmetric errors positive errors or negative errors Otherwise the program uses the same parts as is currently being specified If a dataset name contains non alphanumeric characters its name should be quoted in the expression in back tick characters e g length cm 2 The numpy functionality is particularly useful for doing more complicated expressions For instance a conditional expression can be written as where x lt y x y or where isfinite x a b You often do not need to create a new dataset when For example with the xy point plotter widget you can directly enter an expression as the X and Y dataset settings When you give a direct dataset expression you can define error bar expressions by separating them by commas and optionally surrounding them by brackets For example a 0 1 plots dataset a as the data with symmetric errors bars of 0 1 Asymmetric bars are given as a a 0 1 a 0 1 Linking datasets to expressions A particularly useful feature is to be able to link a dataset to an expression so if the express
56. tion Veusz Veusz is a scientific plotting package It was designed to be easy to use easily extensible but powerful The program features a graphical user interface which works under Unix Linux Windows or Mac OS X It can also be easily scripted the saved file formats are similar to Python scripts or used as module inside Python Veusz reads data from a number of different types of data file it can be manually entered or constructed from other datasets In Veusz the document is built in an object oriented fashion where a document is built up by a number of widgets in a hierarchy For example multiple function or xy widgets can be placed inside a graph widget and many graphs can be placed in a grid widget The technologies behind Veusz include PyQt a very easy to use Python interface to Qt which is used for rendering and the graphical user interface GUI and numpy a package for Python which makes the handling of large datasets easy Veusz can be extended by the user easily by adding plugins Support for different data file types can be added with import plugins Dataset plugins automate the manipulation of datasets Tools plugins automate the manipulation of the document Terminology Here we define some terminology for future use Widget A document and its graphs are built up from widgets These widgets can often by placed within each other depending on the type of the widget A widget has children those widgets placed within i
57. to the list of datasets given To To widgetpath The To command takes a path to a widget and moves to that widget For example this may be the root widget graphl page1 graph1 x x The syntax is designed to mimic Unix paths for files represents the base widget where the pages reside and represents the widget next up the tree Quit Quit Quits Veusz This is only supported in veusz_listen WaitForClose WaitForClose 27 Command line interface Wait until the plotting window has been closed Note this command is only supported in the embedding interface Zoom Zoom lt factor Sets the plot zoom factor relative to a 1 1 scaling factor can also be width height or page to zoom to the page width height or page respectively This is only supported in embedded mode or veusz_listen Security With the 1 0 release of Veusz input scripts and expressions are checked for possible security risks Only a limited subset of Python functionality is allowed or a dialog box is opened allowing the user to cancel the operation Specifically you cannot import modules get attributes of Python objects access globals or locals or do any sort of file reading or manipulation Basically anything which might break in Veusz or modify a system is not supported In addition internal Veusz functions which can modify a system are also warned against specifically Print Save and Export
58. ton to start the capture Click Finish or Cancel to stop Cancelling destroys captured data 16 Chapter 3 Command line interface Introduction An alternative way to control Veusz is via its command line interface As Veusz is a a Python application it uses Python as its scripting language Therefore you can freely mix Veusz and Python commands on the command line Veusz can also read in Python scripts from files see the Load command When commands are entered in the command prompt in the Veusz window Veusz supports a simplified command syntax where brackets following commands names and commas can replaced by spaces in Veusz commands not Python commands For example Add graph name foo may be entered as Add graph name foo The numpy package is already imported into the command line interface as so you do not need to import it first The command prompt supports history use the up and down cursor keys to recall previous commands Most of the commands listed below can be used in the in program command line interface using the embedding interface or using veusz_listen Commands specific to particular modes are documented as such Veusz also includes a new object oriented version of the interface which is documented at http barmag net veusz wiki EmbeddingPython Commands We list the allowed set of commands below Action Action actionname componentpath Initiates the specified action on the w
59. useecs NIES RENIEN EEEE EPEA AE PENNE acess diria 18 Enable Toolbar ecotipos ii li ies 18 EXPO iera tte sims ta ctrl E E E E EE 19 PilterDatasets iii Mess oera eE EE EE EEE E EE E EEE EE EEE E A TE SS 19 ForceU 070 Fe Kre EE E EE E E E sens 19 A ie ed 19 A A a E EE E A E EEE E E E E A E aS 19 GetCliCk cri rE EE ESR A E EEES E EEI TEE E EE a a es 19 EE DET e E E EEE EE EE 20 iii Veusz a scientific plotting package GetDatal y per EEEE E shet i sunegedese cubed eeu EOE tes gteps tue deby huey abe teumeesiont es EEE 20 GetDatasets ui IA eS eae aE a Bape ne oes 20 GPL neta ett de ue tae orto daub a een anes oer tbee de sea gio 20 A e a N a e A cosets Eaa e E E E ter rthe wien cee eelabeeueeaky 20 ImportElle2D a A A E A NO EE 21 TimportBule CSV eean today O UA cas 21 Import Fle HDF esaa a R e S E a E REA E 22 ImiportPile Plein sir pove a eae 22 A 23 porn MO ta A A A o 23 ImportStrins2D nice paws e toi E saems ona thee de repeemeteng dor geu anes gnguadas de 23 O 23 O NN 24 Load O 24 MOVE TOP ario Aa o hnag cenetoutawen T AET A ENNER 24 Reload Datats rece A A O att ee ae ah Sait Te tte 24 O RN 24 REMOVE RA a Se aT ia 24 Resize WING OW setool litis ios 24 O dee S et cine stub ted te Re Mat eam ata tad 25 Dira eta tab nati Sea prat cotpenaded a E s E RE EE E oops iodo 25 SetAntA Hasi s r SS AOS alee 25 ELD Ata NN 25 SetData Expression n o i e A EE etic eh ee ah 25 A ANGE mear OS 25 SetData2 De ioc A E a de ee is 26 SetDataZDEX
60. xis number formatting panel can be given to explicitly choose a format Some examples are given in the drop down axis menu Hold the mouse over the example for detail C style number formatting is used with a few Veusz specific extensions Text can be mixed with format specifiers which start with a sign Examples of C style formatting include 2f decimal number with two decimal places e g 2 01 3e scientific formatting with three decimal places e g 2 123e 02 g general formatting switching between f and e as appropriate See http opengroup org onlinepubs 007908799 xsh fprintf html for details Veusz extensions include Ve which is like e except it displays scientific notation as written e g 1 2x10423 rather than 1 2e 23 Vg switches between standard numbers and Veusz scientific notation for large and small numbers VE using engineering SI suffixes to represent large or small numbers e g 1000 is 1k Veusz allows dates and times to be formatted using VDX where X is one of the formatting characters for strftime see http opengroup org onlinepubs 007908799 xsh strftime html for details These include a for an abbreviated weekday name A for full weekday name b for abbreviated month name B for full month name c date and time representaiton d day of month 01 31 H hour as 00 23 I hour as 01 12 j as day of year 001 366 m as month 01 12 M minute as 00 59 p AM PM S
61. z embed as veusz import time open a new window and return a new Embedded object embed veusz Embedded window title make a new page but adding a page widget to the root widget page embed Root Add page add a new graph widget to the page graph page Add graph add a function widget to the graph The Add method can take a list of settings to set after widget creation Here function x 2 is equivalent to function function val x 2 function graph Add function function x 2 time sleep 2 function function val x 3 this is the same if the widgets have the default names Root pagel graphl functionl function val x 3 If the document contains a page called pagel then Root pagel is the object representing the page Similarly Root pagel graphl is a graph called graph1 in the page You can also use dictionary style indexing to get child widgets e g Root page1 graph1 This style is easier to use if the names of widgets contain spaces or if widget names shadow methods or properties of the Node object i e if you do not control the widget names Widget nodes can contain as children other widgets groups of settings or settings Groups of settings can contain child settings Settings cannot contain other nodes Here are the useful operations of Nodes class Node object 31 Using Veusz from other programs oroperties path return path to object in docum

Veusz - a scientific plotting package

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