stats

This program computes a set of statistics for the pixels in each selected band of an image cube, and outputs the results of each band. By default, all bands are processed. The stats program generates statistics that will help you find new insights in your data to make more accurate predictions and achieve better outcomes.

Histogram Computation

Stats uses a histogram to compute the mode and median DN values for a given cube. The minimum, maximum, and number of bins depends on the pixel type of the cube. Here are the minimum, maximum, and number of bins associated with supported pixel types:

Pixel Type	Minimum	Maximum	Number of Bins
Unsigned Byte	0 * cube multiplier + base	255 * cube multiplier + base	256
Unsigned Word	0 * cube multiplier + base	65535 * cube multiplier + base	65536
Signed Word	-32768.0 * cube multiplier + base	32767.0 * cube multiplier + base	65536
Unsigned Integer	Minimum DN value in the cube	Maximum DN value in the cube	65536
Signed Integer	Minimum DN value in the cube	Maximum DN value in the cube	65536
Real	Minimum DN value in the cube	Maximum DN value in the cube	65536

The cube multiplier and base can be found in the header of the cube.

Output:

The statistics are output to both the screen and the print.prt file in PVL format. Additionally, if the user specifies a file using the TO parameter, the statistics are written to that file in PVL format (default) or as a comma delimited text file (FLAT file), as specified by the FORMAT parameter. For multi-band images, each band has its own statistics information that will be appended to the output file. The contents of the PVL file can be read using the getkey program. The comma delimited text file can be imported into Excel or other applications. The statistics calculated and reported are as follows:

      Average                 Total pixels

      Standard deviation      Valid pixels

      Variance                Over valid maximum pixels

      Median                  Under valid minimum pixels

      Mode                    Null pixels

      Skew                    Low representation saturation (LRS) pixels

      Minimum                 High representation saturation (HRS) pixels

      Maximum                 Low instrument saturation (LIS) pixels

      Sum                     High instrument saturation (HIS) pixels
    

If the output file exists and the APPEND parameter is set to "no," the contents will be overwritten.

How to Specify Bands:

You may process one or a few specific bands if you indicate the band(s) in which you desire to gather statistics. A band may be specified by simply placing a plus sign and the band number after the input filename (e.g., peaks.cub+3). For several bands, commas and hyphens are used to communicate effectively with the program as in the following example: peaks.cub+2,4-6.

This example shows the statistics computed for all bands in the input cube. When no band is specified by the user, stats default behavior is to calculate statistics for all bands in a cube.

stats from=peaks.cub to=peaks0_stats.log

Output from stats application	This is the results captured in "peaks0_stats.log" by the redirection of standard output.

This example shows the statistics computed from band 3 of the input cube. A band may be specified by simply placing the plus sign and the band number after the input filename.

stats from=peaks.cub+3 to=peaks1_stats.log

Output from stats application	This is the results captured in "peaks3_stats.log" by the redirection of standard output.

This example shows the statistics computed for selected bands of a cube. In addition to the plus suffix, the comma and hyphen are used to specify multiple bands from the input cube to process.

stats from=peaks.cub+2,4-6 to=peaks2_stats.log

Output from stats application	This is the results captured in "peaks2_stats.log" by the redirection of standard output.