ANSI-C programs: histogram_ras.c
NAME
histogram_ras - Calcualtes histogram_ras of test-area values
(polygon regions).
SYNOPSIS
histogram_ras <ras_in> <polygon>
<histogram_rass> <mean/stdev> <percent>
[lr_flag] [start] [stop]
| <ras_in> | input 8-bit SUN raster/BMP image file (SUN raster: *.ras, BMP image format: *.bmp) |
| <polygon> | polygon data file |
| <histograms> | calculated histograms (output) |
| <mean/stdev> | calculated mean/stdev (output) |
| <percent> | calculated percent of histograms (output) |
| [lr_flag] | input left/right flipped (default=1: flipped; -1: not flipped) |
| [start] | first histogram class (default=0) |
| [stop] | last histogram class (default=all values) |
EXAMPLE
histogram_ras 1352_1610.landuse.ras 1352_1610.poly
1352_1610.landuse.hist 1352_1610.landuse.dat
1352_1610.landuse.perc -1
Extracts image values from the SUN raster file(landuse classes) and writes for each polygon region the histogram, the mean and stdev, and the percent to the output files.
INSTALLATION
Source code histogram_ras.c in $LAT_HOME/src. For compilation
adjust and use Makefile: Executable version histogram_ras in
../bin
AVAILABILITY
Uses display programs definition file display.h, SUN raster file definition file
rasterfile.h, and BMP format
definition file, bmp_image.h
DESCRIPTION
histogram_ras extracts SUN rasterfile values for test
areas defined by polygons. For each polygon region the histogram,
mean, standard deviation, and percent are calculated and written
to the corresponding output files.The range between the selected
minimum and maximum values is used for the histogram. Each class
corresponds to a single image value, resulting in a maximum of
256 classes for an 8-bit image.
The program determines how many times values in a certain interval are found for a certain polygon region. The result is normalized with the total number of pixels, i.e. the sum of all the histogram_ras values for a certain polygon is 1.0 If the image is left/right flipped relative to the polygon coordinates (respectively relative to the original SAR image geometry) the left/right flipping flag has to be set to -1. The selection of the polygon regions is supported with the program polyras.
OPTIONS
The output histogram, mean and standard deviations, and percent
are written to textfiles and may therefore easily be imported,
displayed and printed by most commercial plotting software.
SEE ALSO
polyras, histogram, display.h, rasterfile.h, bmp_image.h.
DIAGNOSTICS
All messages are generally self-explanatory.
NOTES
none.
© Copyrights for Documentation, Users Guide and Reference Manual by Gamma Remote Sensing, 2000.
UW, CW, TS, last change 24-Jan-2000.