ClassificationStatistics Task

This task computes statistics on a raster.

Example

The following example performs an ISODATA classification on the raster, then computes the statistics.

; Start the application

e = ENVI()

; Open an input file

File = Filepath('qb_boulder_msi', Subdir=['data'], $

  Root_Dir=e.Root_Dir)

Raster = e.OpenRaster(File)

; Run an ISOData classification on the input raster

IsoTask = EnviTask('IsodataClassification')

IsoTask.INPUT_RASTER = Raster

IsoTask.Execute

; Get the task from the catalog of ENVITasks

Task = ENVITask('ClassificationStatistics')

; Define inputs

Task.INPUT_RASTER = Raster

Task.INPUT_CLASS_RASTER = IsoTask.OUTPUT_RASTER

Task.OUTPUT_REPORT_URI = e.GetTemporaryFilename('txt')

; Run the task

Task.Execute

; Print Statistics

Print, Task.MAX

Print, Task.MEAN

Print, Task.MIN

Print, Task.NPIXELS

Print, Task.STDDEV

Syntax

Result = ENVITask('ClassificationStatistics')

Input properties (Get, Set): CLASSES, COMPUTE_COVARIANCE, COMPUTE_HISTOGRAMS, INPUT_CLASS_RASTER, INPUT_RASTER, OUTPUT_REPORT_URI

Output properties (Get only): CORRELATION, COVARIANCE, EIGENVALUES, EIGENVECTORS, MAX, MEAN, MIN, NPIXELS, STDDEV

Properties marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Properties marked as "Get" are those whose values you can retrieve but not set.

Methods

This task inherits the following methods from ENVITask:

Properties

This task inherits the following properties from ENVITask:

COMMUTE_ON_DOWNSAMPLE

CLASSES (optional)

Specify which classes to use to generate statistics.

COMPUTE_COVARIANCE (optional)

Set this to true to compute covariance matrix, eigenvectors, eigenvalues, and correlation. The default is false.

COMPUTE_HISTOGRAMS (optional)

Set this to true to compute histograms.

CORRELATION (optional)

This is the correlation matrix of the data for each class.

COVARIANCE (optional)

This is the covariance matrix of the data for each class.

EIGENVALUES (optional)

This is the eigenvalues of the data for each class.

EIGENVECTORS (optional)

This is the eigenvectors of the data for each class.

INPUT_CLASS_RASTER (required)

Specify a classification raster to use for statistics generation. The pixels from each selected class will produce its own set of statistics.

INPUT_RASTER

Specify a raster to use for statistics generation.

MAX (required)

This is the maximum data value of each band.

MEAN (required)

This is the mean data value of each band.

MIN (required)

This is the minimum data value of each band.

NPIXELS (required)

This is the number of pixels for each class.

OUTPUT_REPORT_URI (optional)

Specify a string with the fully-qualified path and filename of a text file that will contain the statistics.

STDDEV (required)

This is the standard deviation data value of each band.

Version History

ENVI 6.1

Introduced

API Version

4.3