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Next: What is a Biplot? Up: XLS-Biplot User's Manual (Version Previous: Introduction

Subsections



Basics of XLS-Biplot

If you want to build a Biplot, you should have at least a rectangular data matrix where columns correspond to some numerical variables and rows to cases or individuals (or other kind of data matrices such as count data in a contingency table). To learn about Biplots and what data is suitable to build biplots in XLS-Biplot, see section 3.

To load a simple data matrix into XLS-Biplot, just prepare a text file with a data row in each line, putting spaces or tabs between numbers and use the Read data item in the File (Biplot in Unix version) menu. See section 4.1.

Then, you will be asked for the kind of data analysis you want to be applied to your matrix and the type of Biplot to use. A recommended first choice is "PC with normalization". Each choice produces different biplots, some of them can not be applied to some kind of data, you shuld know what kind of analysis is suitable for your data. See section 3.1 for a discussion on all this.

After the data analysis has been chosen, the Biplot window will appear and you should choice the kind of Biplot (how the final coordinates are computed): choose the Biplot type... item in the Biplot... menu button, see section 3.1.

The Biplot window has three main areas: the plot, the toolbar and the message rectangle (at the bottom of the window). While you move the mouse, relevant messages are shown in the message area. Detailed discussion on using the menus and tools in the toolbar can be found in section 5.

For brief help, click on the 'Help' tool button. The window enters in 'Help mode': further clicks on several parts of it will provide you with different help pages. Also, choosing any item menu will show a help page for it. To exit 'Help mode', click again on the Help button.

How to do some basic tasks

* To enter your data and make a Biplot
use the Read data... item in the File (BiplotMenu in Unix) menu (menu bar). Simple numerical data matrices are accepted, but if you want to enclose more information about your data (variable and/or case names, weights, etc.) you should use the Biplot file format, see section 4 of this manual. You may want to use Excel or a similar program to prepare the input file. Look at the file biplot-template.xls in the examples directory for a template to prepare your data file.

* To modify the plot
Using the 'Edit' tool available in the Biplot Window, you can modify some of the elements of the plot: the axis (including frame and grid), the arrows, the points, the labels, even the biplot type and the data processing in use (see section 5.2.4). The 'Move' tool is for improving labels position, or to resize arrows. Take a look on section 5.2.6.

* To inspect your plot and your data
The item Save Biplot report... in the Save button available in the window toolbar gives you a report on the data in the Biplot and the way it has been computed (check the button Open in a text window if you don't need to save the report in a file. To get a closer view, using the Info tool, you point with the mouse to any point or any arrow and you see information on it in the message rectangle. If you do want more information on the element, just click on it and some text window will pop up. (See section 5.3 on dealing with those text windows).

* To relate your data to the plot
Using the Show original or 'Show transformed items in the 'Biplot' menu available in the toolbar, you get a data sheet window showing the appropriate data matrix. These data sheet widows are linked to the Biplot window, when you select cases or variables in any one of them, the selection is also hilighted in the other. See section 5.4 on working with data sheet windows.

* To save or reuse your work
use the Save... button to acces some 'Saving' items. You can save your data using the Biplot format, you can see and/or save a textual report on the current Biplot, you can save your entire Biplot window with all the changes you made on it. See section 4.3.

* To print the Biplot graphic
with good quality graphics, go to Save graphic as... item in the Save button of the biplot's window. Check the PDF format and click OK. Then use Acrobat to print the file. (If you have trouble doing this, see 6 or A).

* To export the Biplot graphic
and use it in other software you use the Save graphic as... item in the Save button. Under MS-Windows, you can go to the standard Edit menu and copy the contents of a Biplot window. Then you can paste it on many other places. To get a better resolution copy of the graph, read carefully the section 6 on how to translate it to postscript or EMF formats, or other. Good quality printing of the plot is also done this way.


XLS-Biplot main menus

XLS-Biplot main menus are installed in the main menu bar in the MS-Windows version, and in a single menu in the menu bar in the Unix/X11 version. These are the items that can be found in any case.

Read data
This is for opening files that contain data to be represented in a Biplot. There two kind of files, simple data matrix or Biplot data. See section 4.
Paste data from clipboard
If you have some data matrix copied into the clipboard, this item gives you a (rather non-standard) way to paste it into an XLS-Biplot window. Just follow the step by step directions.
Load XLS-Biplot object
If you saved one of your XLS-Biplot windows using Save XLSBiplot object" in the Save button, you can restore the window using this item. See section 4.3. There are some sample files (extension .bplsp) in the examples directory.
Make example
To test the capabilities of XLS-Biplot it may be convenient just to have some Biplot based on random data. This item makes it.
Copy to clip
In the MS-Windows version, this item places a bitmap copy of the active window in the clipboard. See section 6.
Configure Helpers
This item raises up a dialog for giving the paths to some appplications used by XLS-Biplot to perform graphics conversion and other task. See appendix A.
Help
Opens a help window with some basic help to use XLS-Biplot.
Open HTML manual
It will open it, if the path to your web browser is correctly specified in the Configure Helpers dialog, and if this user's manual is installed in a folder named users-manual-html within the directory that contain the XLS-Biplot files.


Using XLS-Biplot through the Web

As a starting point for an ongoing project, Biplots can be get from the Web by entering
http://tukey.upf.es/bp-form.html
in your Web navigator.

You should have a (not very large) data array of numbers in the clipboard. You paste your data in the provided text area and you get your Biplot back as a compressed graphic (png format), and also the finer postscript and pdf versions.

This is a really inmature version of a fully configurable web service, we hope to work on it to make it really useful.


next up previous
Next: What is a Biplot? Up: XLS-Biplot User's Manual (Version Previous: Introduction
Frederic Udina
2005-03-15