The Dialogs

Function
The dialog Function is used to create and perform the settings for function plots. It looks the same for 2d, surface, pie and 3d plots. Only a few plot specific things differ. Especially the Style is different for surface plots.
The first lineedit contains the expression for the plot function. The entered expression is evaluated via a powerful parser. For a complete list of supported functions see the parser section.
the second lineedit is for setting the label of the created graph. This is the label which you see in the legend.
In the "Range" and "Number of Points" section you can select the range and the number of points for the created function.
With the remaining style items you can influence the appearance of the function. If you create a normal function the first selection defines the line style (Lines, NoCurve, Steps, Boxes, Impulses, Y Boxes), the color and if you want to have it filled (with a different color). The other items select the symbol for the plot points, with color, size, if it should be filled and with which color. If you create a surface plot you have the possibility to select whether to show a density or contour plot, or both. Then you can select the number of levels for contour plots and the colorscale for density plots.
For changing the settings of a function you have to select the change button in the list dialog. For changing the style of a surface plot you can also use the "Plot Settings" dialog.
Since version 1.4.0 LabPlot uses the new QWT 3D Plot which should be preferred to the simple 3d plot.

Data
The dialog Data is used to create graphs from data files.
This dialog looks very similar to the function dialog. There are some differences though. You have to select a data file to open in the first lineedit. You can use the "New" button to open a file dialog for this. In the "Read from column" section you can enter from which column you want to read the corresponding values. If unsure use the check button to have a look at the data file. You can select here also from which to which row to read data and what separating character is used. The "auto" separation detects all number and combination of whitespaces.
When using "y1 | y2 | y3 | ..." in the "read as" selection the y-values are read from one line in the data files.
LabPlot supports the reading of images (all supported formats) and compressed data too (gzip, bzip2). for images you should select "matrix" to read the data of the image.
Since version 1.3.1 LabPlot can also read HDF5, netCDF, CDF and audio data (*.wav,*.au,*.aiff,*.snd,...). For netCDF and CDF data just select the variables in the x,y, etc. line edits and maybe check it in the "check data" dialog. For finding the correct variables you can use the file info dialog to check the content of a netCDF/CDF file. When reading audio data just select 1 for the time, 2 for the first channel and 3 for the second channel. 0 of course means index like when reading any other data file.
The "Read As" section selects the kind of data in the data file. The "Graph Type" selects the type of graph to create. From x-y data you can make only 2 dimensional plots. From x-y-z data you can create error and surface plots (2D data dialog) or density, contour or 3d plots (3D data dialog). From matrix data you can create density or contour plots (2D data dialog) or 3d plots (3D data dialog).
Since version 1.4.0 LabPlot uses the new QWT 3D Plot which should be preferred to the simple 3d plot.

Plot List
In the plot dialog you can manipulate the plots in a worksheet. You can clone or delete plots here.

Graph List
The list dialog is the central point for dealing with the different graphs of a plot. Here you have an overview of all graphs and you can manipulate them. You can reach the list dialog via the Plot->GraphList menu or by double clicking inside the plot. All mentioned functions can be reached in all list dialogs with the
With "Show/Hide" you can toggle the state all selected graphs. Only "Shown" graphs are visible in the plot. The autoscaling function also uses only the visible graphs.
With the buttons "Add Datafile" and "Add Function" you can add a graph from data or function to the plot. (see function dialog or data dialog. ) With "Delete" you can easily delete the selected graph. With "Change" you can change the settings of the selected graph. If you just want a copy of an existing graph use the "clone graph" button.
The "Export" button opens the dump dialog to export a graph to a file and the "Edit" button gets you to the edit dialog.
With "Toggle Masking" and "Unmask All" you can change the masking of different data points.
The "Statistics" button shows some statistics about the selected graphs.
Every manipulation can also be reached via the right mouse button. Multiple selections are possible.

Add Graph
Here you can add graphs from another worksheet or from any spreadsheet.

Import Dialog
With the import dialog you can import data into LabPlot.
In the line edit you can specify multiple data files to read. The "File Info" button shows you some informations about the selected files. You can also specify the separating character (for instance ",") and the comment line character. The start and end row to read can also be customized here.
Since version 1.4.1 of LabPlot you can select pre-defined filter for different standard data formats that select all needed settings. Also support for binary data import was added with this release.

Edit
With the edit dialog you can easily edit the data of a graph. You can reach this dialog via the list dialog.
The table on the top side shows you all the data. Here you can select which rows and columns you want to edit. You can delete or sort selected rows ascending or descending with the buttons under the Table. You can also evaluate an expression to the selected rows and columns. Here the same powerful parser features like in the function dialog can be used. For a list of available functions see the parser section.

Objects
With the objects dialog you can change the settings of all drawing objects. The object dialog can be found in the appearance menu.
There are 5 tabs for every type of drawing object. Line, Label, Rect, Ellipse and Image. For every object type you can define up to 10 different objects. All settings can be changed in this dialog. If you want to delete an object, select the object in the object list and push the "delete object" button.
If you want to create objects, you can use the items in the drawing menu. The objects then can be moved with the mouse. Double-click on an object opens the corresponding tab of the object dialog.

File Info
The file info dialog can be reached from the data dialog. Here you can find a lot of informations about a data file. Especially for HDF5, netCDF, CDF and audio files you can have a look at the internal structure of a data file.

Dump
The dump dialog can be reached from the graph list dialog. Here you can export a graph to ASCII, HDF5, netCDF, CDF, audio, binary or an image file. Every type of file has special options. You can also specify the range of data to export.
For ASCII data the file is automatically compressed when appending .gz or .bz2 to the filename.

Appearance
With the four appearance dialogs you can influence the settings of the active plot. You can reach this dialogs via the "Appearance" menu or by double clicking on the object in the plot.

Plot Settings
The graph dialog lets you select the background color, the graph background color (inside the plot) and the ranges for the different axes. Also marker or baseline settings can be changed here. The autorange functionality can also be reached from the side tool bar. If you have a surface plot you can also change the style settings here.
If the active plot is a QWT 3D plot you can select some special settings here. The plot style changes the surface of the 3d mesh. The coordinate style changes the coordinates. The floor style enables contour or density plots on the floor with a user specified number of isolines. Finally you can select a special colormap (139 different colormaps are provided by LabPlot per default).

Worksheet Settings
With the worksheet dialog you can change the title of a worksheet and the timestamp. The title and timestamp can be enabled or disable here too.

Axes
The axes dialog lets you change the settings for the different axes. It opens if you click on one of the axes.
In the upper region you have a list of all axes. Here you can select the axis to change. To enable or disable the axis use the checkbutton at the top of the dialog. Under the axes list you have different tabs to change a lot axis settings (color, tics, grid, etc.).

Title
In the title dialog you can change parameters of the title (label, size and font). The dialog open with double clicking on the title.

Legend
In the legend dialog you can change parameters of the legend (boxed, size and font). The dialog open with double clicking on the legend.

Analysis
With the analysis dialogs you can analyse a graph with different methods. By applying a method you create a new graph which is inserted in the active plot.
All analysis functions allows you to select the destination for the resulting data. You can add the result to any existing worksheet/spreadsheet or to a new worksheet/spreadsheet.
Most of the analysis functions can also be applied to a spreadsheet. From the selected columns of the spreadsheet a new column with the resulting values is created.

Analysis functions of LabPlot
Name	Description	Parameter	Applies to
Data set operations	If you have at least two graphs in the active plot you can operate on this data set in this dialog. You can add, substract, multiply and divide data sets here.	two datasets
Average	With this function you can average over n points of a graph. The number of points is reduced by a factor of 1/n.	number of points to average	everything
Compress	This function can compress large datasets to less points. You can select whether to sum or average over a certain number of points.	sum or average; number of points	everything
Smooth	This function does the same as average but for every data point. So you will get a smoothed graph with the same number of data points.	number of points	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY, X-Y-Z
Prune	This function reduces the number of data points by just using every n-th point. The resulting number of points is reduced by a factor of 1/n.	number of consecutive points	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Periodical Functions	This function can be used to reduce a dataset to one period of a function. You can select whether to sum or average.	sum/average; points per period	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Seasonal	This function can calculate the difference (or sum) of on period to the next one. The period is specified by the number of points in it.	sum/difference; points per period	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Peak find	This function allows you to find the peaks (also negative peaks) in a data set. The sensitivity for finding peaks can be specified with the parameters threshold and accuracy	positive/negative peaks;threshold (Y-Range); accuracy (X-range)	X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Histogram	With this function you can make a histogram of a graph. That means that the y-range is separated in n bins and every datapoint fitting in one bin is counted.	used Y-range; number of bins	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY, MATRIX
Interpolation	Interpolation tries to find a smooth curves through a given set of data points. You can use different types of interpolation to do that : linear, polynomial, cspline, akima. All datapoints in the active region are used for interpolation.	interpolation type; range/number of points for interpolating function	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Differences	This dialog creates an approximation of the first derivative of a graph.	None	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Integration	This function can be used to numerical integrate a graph. With the "Add Graph" checkbox you can select whether to add the integrated graph. With the "Show Info" checkbox selected the cumulative sum is shown in a separate window.	baseline/region for integration; sum or area (absolute values)	SPREADSHEET, X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Regression	The regression function can be used to fit a graph with polynomials up to the 10-th order.	weight/model; number of points/range for regression function	X-Y,X-Y-DY,X-Y-DX-DY
Fourier Tansform	With this function you can calculate the fourier transform of a graph. LabPlot can use the FFTW or GSL library for that. You can select whether to transform forward or backward.	X-values:index/frequency/period; Y-values:magnitude/phase/real part/imaginary part	X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Convolution/Deconvolution	With this function you can calculate the convolution of one graph with another. LabPlot uses the FFTW of GSL for that. It is also possible to deconvolve a set.	X-values:index/same as signal	X-Y, X-Y-DY, X-Y-DY-DY + X-Y, X-Y-DY, X-Y-DY-DY
Nonlinear Fit	With this function you can fit a graph in a nonlinear fashion. You can select one of 12 different models or any user defined function with up to 9 parameters. Please note that fitting especially exponential models is very sensitive to the initial values. The resulting fit parameter are shown in the bottom field and automatically replaced as initial values for further fitting. The results are added to the plot as label.	fit function;initial values;baseline/region for fitting; range/number of points for fit function	X-Y, X-Y-DY, X-Y-DX-DY, X-Y-DY-DY
Image Manipulation	In this function you can manipulate matrix or image data of the active plot (for instance a surface plot). LabPlot uses the API of ImageMagick to convert the image with about 50 different methods.	size (height/width) of resulting image	MATRIX,IMAGE

Arrange
In the arrange dialog you can specify how to arrange plots on the worksheet. With 2x2 the plots are arranged in a 2x2 grid with a distance of gap between them and the border of the worksheet.

Overlay
In the overlay dialog you can simply overlay a plot onto another. Of course you need to have at least two plots in a worksheet to use this.

QSA Workbench
LabPlot uses the Script for Applications (QSA) extension of to use scripting. To create and edit scripts QSA includes the QSA workbench which can be used in LabPlot too.
For more informations take a look at the Scripting Chapter