7.8 Draw histograms.

The 2-D histogram displays frequencies as color coded cells, which size could be adjusted by changing the Number of intervals (from 10 to 150) and the min and max limits attributed to X and Y axes. The associated colors of Intensity scale are shown on the right side of the histogram. The user may change the X and Y axes to time (in years), latitude, longitude, depth, and any of the four magnitudes. To confirm the choice and redraw 2-D histogram, click button  .. 
The button allows the user to zoom on an area of interest in a 2-D histogram. Toggle the button, bring the cursor on the histogram plate, outline the area of interest by pressing the left mouse button and dragging the cursor. (With the left mouse button pressed at any place of the histogram plate the program displays the cursor XY coordinates. Clicking the right mouse button will zoom out the display one step back . Zooming can operated as often as possible.)

The button allows the user to switch Intensity scale from linear to logarithmic one. To switch scales toggle the button and redraw histogram.
To display a traditional 1-D histogram either for X- or Y-axis click either button  or , respectively. Traditional histograms displays frequencies as bars of different heights.
 

The user may wish mapping catalog characteristics that differ from the default frequencies. Specifically, there are four optional choices of the histogram Type - frequency, weighted, minimum, maximum. The default type frequency denotes as Intensity the number of events inside a cell on the map. When minimum (or maximum) type is invoked the lower frame of the tab becomes active permitting the user to make a choice from Depth and magnitudes (m1, m2, m3, m4), which minimum (or maximum) in each cell will be mapped.

 

 

When weighted type is invoked the tab Weight becomes active. In this case CompiCat provides making a choice between sums of earthquake energy, area, and length, as well as the user defined 10^a*^m+b weights (where a and b are arbitrary constants, and m is the earthquake magnitude). These quantities permit better understanding the distribution of the energy release, or the area ruptured, or the total length of ruptures in the area of interest. Open Weight tab to define the choice and specify weights, which will be used for calculation and mapping of weighted sum in each cell.

   

To produce series of histograms toggle Invoke by List button . Make the choice of an additional parameter, Number of intervals (from 2 to 20), and the min and max limits to be used. Toggle button Switch image scale to specify either a common or interval dependent normalized scales of intensity. Click either of Redraw buttons to display a series of 1-D or 2-D histograms. Click  or button to display the previous or the next histogram in a series.

If needed, invoke help text on buttons by clicking , then click a button to get the appropriate quick help on it.

  opens the dialog for printout. (Note that a histogram image can be saved in the PostScript format by using print to file option.)
 saves a histogram image as a PDF file
saves a histogram table as a Comma Separated Values (CSV) Microsoft Excel file. Note that there might be a problem in reading CSV format files due to Regional Options and Microsoft Excel International Options (see Appendix C. Platform Notes).