Histogram

A Histogram is a bar graph that shows how frequently data occur within certain ranges of intervals. The height of each bar gives the frequency in the respective interval.

To generate a histogram based on a layer, it is necessary to define the attribute and the number of intervals (slices).

It is accessible through:

    Layer  > Histogram...  
  1. Property  - select the numerical attribute to generate the histogram.
  2. Number of slices - select the number of intervals (slices) if the attribute is a number.
  3. Press OK to generate the histogram or Cancel to close the dialog.
  4. A summary function can be chosen if the histogram is being generated based on a linked dataset, otherwise this option won't be visible.
  5. Graphic Style  - used to change color, title, X and Y labels, font style, grid and so on through the chart style interface.
It is also possible to interact with the histogram plotter area highlighting some data, zooming in or out. See the details on how to do that here.

 Note: If the attribute chosen is not numeric, all unique values are treated as intervals.
Note: When the histogram is based on a raster file, the histogram will be divided according to all pixel values.

Note: When the histogram is based on a raster file,  setting the number of slices to 0 means all the of the pixel values will be used to generate the histogram, otherwise the pixel values will be divided within the informed number of slices.

Note: If the histogram is based on a raster file and the selected band does not inform the dummy value, or inform a wrong one, than any pixel with that value will  be used while calculating the histogram's intervals and frequencies, which can generate a histogram with unexpected frequency values.