Wednesday, June 6, 2012

New VisuMap release with multi-band spectrum view

I have just released VisuMap 3.5.879. Worth mentioning in this release is the spectrum band view to visualize large tables. The spectrum band view displays a table as multiple bands of spectrums with one spectrum for each data row or data column.  The spectrum band view is relatively simple to implement and to understand, it is amazingly effective to capture the value distribution of variables and to compare large number of variables. The following picture shows a scenario how VisuMap goes about exploring a large data table with the spectrum band view:

In this example, the data set  is a 4000x1700 number table. Each of the 4000 rows represents a compound with about 1700 physical and chemical features. On the top left side the data set is displayed in a PCA map with one dot for each compound (5 clusters are discernible.)  On the top right side, the data set is displayed as a heat map with one line for each data row. We have selected about 60 features from the heat map and shown them in a spectrum band view at the lower right side. The spectrum band shows each feature as vertical spectrum. We see that most features are more or less Gaussian distributed; some features are discrete as their spectrum comprise only isolated bars.

The spectrum band also helps to answer a frequently asked question in data analysis, namely: if the value of  one feature is in certain range, how will the values of other features be distributed? We can do this very simply with the spectrum map as illustrated in the following picture:

In above picture we have displayed 8 features in a spectrum band with 8 horizontal spectrums. We have selected with the mouse point a small section in the first feature, the spectrum band view immediately shows the density curve (i.e. the distribution) of the other features of selected objects.

Furthermore, with the spectrum band view we can record a series of selections, then repeatedly replay the selection in animation as shown in the following video clip: