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- A free parallel coordinates software

XDAT User Manual

Importing Data

Before being able to do anything useful in XDAT, you first need to import data. All data to be imported must be in ascii format and should be split in columns, as if you wanted to import it into e.g. Excel. The data may or may not have headers in the first line.

To get started, you can test the software using the sample file included in the distribution. It is called Example_data.txt.

Import Settings

Before importing data for the first time, you should define the import settings. Click on "Import Settings" in the "Options" menu. This brings up the following dialog:

Import Settings

The upper section allows you to choose the default location for file browsing dialogs.

The middle section lets you choose how the data columns are delimited. If you choose "other", you can type a delimiting character into the adjacent text field.

The checkbox in the lower right corner of the middle section lets you specify whether consecutive occurrences of the delimiting character should be treated as a single one.

The lower section lets you specify the number format. Choose US for data which uses periods as decimal character and German for data which uses commas as decimal character. The respective other character is used as digit grouping symbol.

Data with Headers

If you want the parameter names to be recognised by XDAT upon import, the first line of your file should contain these parameter names, delimited in the same way as the data itself.

To import the data, choose "Import data with headers" in the "Data" menu. In the upcoming dialog, select the file containing the data. If after the import the data is not split into columns as you expected it, go back to the import settings to verify your delimiter settings.

Data without Headers

To import data that does not contain any headers, choose "Import data without headers" in the "Data" menu. In the upcoming dialog, select the file containing the data. If the data is not split into columns as you expected it, go back to the import settings to verify your delimiter settings.

Updating Data

If you have already created charts (and possibly also modified/customised them), you will notice that when trying to import data with the options described above, you will be warned that all charts will be closed. However, if the data you want to import has the same number of parameters as the one currently loaded, you can update the datasheet without closing the charts.

Choose "Update data with(out) headers" from the "Data" menu. The datasheet will be updated and all charts will be rebuilt based on the updated datasheet.

Note that if designs had been grouped in clusters this information will be lost after the update.

Parameter Types

XDAT supports two different parameter types:

Numeric parameters are parameters that can be expressed with floating point values.

If for any design in the datasheet the value of a parameter can not be parsed into a floating point value, the parameter is assumed to be non-numeric. As a result, each value that was found for that parameter will be represented by a tic on the axis, irrespective of the display settings that were made for that axis.

Editing Data

XDAT mainly relies on the data being imported from an external source. If fundamental changes must be made to the datasheet it is easiest to edit the data in a separate application and reimport it into XDAT afterwards. However, some basic functionality is provided to edit data.

Editing single Values

You can edit single values of the data table by double-clicking into a cell and typing in a new value.

If any charts are open they will be updated to reflect the change.

Removing Designs

Select the designs you want to remove. Then, select the menu item "remove selected designs" from the "data" menu. Since release 2.2 you can also select designs in parallel coordinate charts directly.

remove_designs.png

If any charts are open they will be updated to reflect the change.

Removing Parameters

From the "data" menu select the menu item "remove parameter". A submenu with a list of existing parameters will open up. Select the parameter you want to be removed.

If any charts are open they will be updated to reflect the change.

remove_parameter.png

Changing Parameter Order

You can change the order of the parameters by left-clicking a column header on the datatable and dragging it to the desired location as shown on the screenshot below.

If any charts are open they will be updated to reflect the change.

dragging_column.png

Alternatively, you can use the chart's context menu entries "move left" and "move right" to move an axis or, even easier: Left-click on the axis and drag it to the desired location (since version 2.0).

(Un)selecting Designs

You can select designs in the datasheet table simply by clicking them. Hold the shift key to select continuous intervals. Hold the control key to select more than one interval. Unselect all designs by either hitting the Escape key or choosing "Unselect all designs" from the "Data" menu. The design selection will influence the display of charts under certain chart configuration conditions.

Creating and using Parallel Coordinate Charts

Creating a new Chart

In order to create a chart, simply choose "Create Parallel Coordinates Chart" from the "Chart" menu.

Choosing Parameters

In the chart, use the "Parameters" menu to choose the parameters you want to be displayed.

parameters.png

You can directly (un)select single parameters in this menu, but if you want to make several changes at once, it might be more convenient to choose "Custom Selection", which brings up a new dialog in which parameters can be (un)selected.

custom_parameter_selection.png

Alternatively you can use the chart's context menu "Hide axis" to unselect a parameter from display (since version 2.0).

Using Filters

In order to filter the data, you can drag the small triangles on top and on the bottom of each axis with the mouse as shown in the picture below. You will notice that this removes designs from the display, depending on whether they cross the axis above or below the filter you are currently dragging.

While you are dragging a filter the filter's value is displayed right next to it unless the parameter being filtered is a non-numeric parameter.

filter.png

Alternatively, you can filter data by dragging a rectangle over the axes you want to filter. ALl designs that cross the selected axes within the drag region will remain visible, the others will be filtered.

Customising Charts using Display Settings

You can customise many settings of how the chart is displayed. To do this, choose "Display Settings" in the "Options" menu of the chart, which brings up the dialog shown below.

chart_display_settings.png

On the first tab titled "General" you can make the following settings:

The second tab titled "Axis-specific" provides the following options:

axis_display_settings.png

If you want to change the settings in general and make the new settings your preferences, you can do this by choosing "Default Display Settings" in the "Options" menu of the main window.

Using the Context Menu (Since release 2.0)

Since release 2.0 the parallel coordinate chart provides a context menu with the following entries:

parallel coordinates chart context menu

Changing the Display Settings directly with the Mouse (Since release 2.0)

The probably fastest way to change the display is using the mouse.

Exporting a Chart to a png Image

In order to export a chart, simply choose "Export to png" from the "Options" menu. (Since release 1.8)

Creating and using 2D Scatter Charts (Since Release 2.0)

2D Scatter Chart

Creating a new Chart

In order to create a chart, simply choose "Create Chart 2D" from the "Chart" menu.

Customising Charts using Display Settings

You can customise many settings of how the chart is displayed. To do this, choose "Display Settings" in the "Options" menu of the chart, which brings up the dialog shown below.

scatter chart display settings

The upper part of this dialog is explained in the section Using Filters and/or the Datasheet Selection.

Right below comes a section which lets you customize the x- and y-axis. Change the plotted parameters for each axis on the fly by simply clicking them in the lists.

Below the parameter selection list the following settings can be made for x- and y- axis individually:

The bottom section allows to make further, general customizations to the display settings:

Furthermore, you can use the bottom two buttons to save the current settings to defaults and to restore default settings, respectively.

Using Filters and/or the Datasheet Selection

The display settings dialog's top section called "Display Mode" provides three options:

Exporting a Chart to a png Image

In order to export a chart, simply choose "Export to png" from the "Options" menu.

Clustering

XDAT allows you to build groups of designs and display them in different colors or remove them from the display. These groups are called clusters.

clusters.png

Creating a new Cluster

clustering.png

Adding Designs to a Cluster

First, use filtering to remove all designs from the display that should not go into the cluster. Then, go to the "Clustering" menu, select "add filtered designs to cluster" and then choose the cluster you want to add the designs to.

Clustering Options on the Side Panel

The whole process of clustering became a lot easier in release 2.2. You can now use the "Add Cluster" button on the chart frame side panel. The new cluster will be shown below.

Use the "Apply" button to add all visible designs to the cluster. Click on the name to change it. Use the other controls to change the color and transparency, (de)activate or remove the cluster.

clustering_side_panel.png

Working with Sessions

XDAT provides a functionality to save the current state of your work to a so-called session file. When reloading this session file, the datasheet and all charts are loaded with all the settings made before saving.

Saving a Session

In order to save a session click "Save Session" in the "File" menu.

You may also save a session under a different file name by clicking "Save Session As" in the "File" menu.

Loading a Session

In order to load a session click "Load Session" in the "File" menu.

Working with large Datasets

I have received feedback from users stating that XDAT was reasonably performant compared to other tools with similar functionality. Nonetheless, when working with large datasets you will still experience performance issues. However, there are some steps you can take to optimize performance.

Settings affecting Performance

The easiest thing you can do to speed up the rendering of parallel charts is switching off both anti-aliasing and transparency. They make the chart prettier but slow down the repainting by an order of magnitude. See section "Customising Charts using Display Settings" to see how to adjust both settings.

Data Criteria affecting Performance

Another thing you can do is avoiding string variables. They require some additional internal calculations that can become slow when the data set is large.

Increasing the Heap Size

As all Java applications, XDAT runs in the so-called "Java Virtual Machine" (JVM). The JVM allocates a part of your RAM and makes it available to XDAT. There is a limit to the amount of memory that is used by the JVM and by default the JVM tries to set this limit to a smart value. However, in order to be able to read large datasets you may want to increase that limit.

When launching XDAT from the command line, you can do just that by adding an additional argument. E.g., to allocate 2.5GB of memory you can run XDAT with the following command:

java -Xmx2500m -jar xdat.jar

In the above command, the 2500 is the allocated heap size in megabytes. So just replace that number with whatever you need.