ROIStatistics Task

This task computes statistics from one or more ENVIROIs and their associated raster. The ROI statistics can be used as input to supervised classification methods.

Example

; 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)

RoiFile = Filepath('qb_boulder_roi.xml', $

ROOT_DIR=e.Root_Dir, $

SUBDIRECTORY=['data'])

Rois = e.OpenRoi(RoiFile)

; Get the task from the catalog of ENVITasks

StatTask = ENVITask('ROIStatistics')

; Get training statistics

StatTask.INPUT_RASTER = Raster

StatTask.INPUT_ROI = Rois

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

StatTask.Execute

; Run SAM classification

ClassTask = ENVITask('SpectralAngleMapperClassification')

ClassTask.INPUT_RASTER = Raster

ClassTask.MEAN = StatTask.Mean

ClassTask.CLASS_NAMES = StatTask.ROI_NAMES

ClassTask.CLASS_COLORS = StatTask.ROI_COLORS

ClassTask.Execute

; Add the output to the Data Manager

e.Data.Add, ClassTask.OUTPUT_RASTER

; Display the result

View = e.GetView()

Layer = View.CreateLayer(ClassTask.OUTPUT_RASTER)

Syntax

Result = ENVITask('ROIStatistics')

Input parameters (Set, Get): INPUT_RASTER, INPUT_ROI, OUTPUT_REPORT_ROI

Output parameters (Get only): COVARIANCE, MAX, MEAN, MIN, ROI_COLORS, ROI_NAMES, ROI_PIXEL_COUNT, STDDEV

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

Input Parameters

INPUT_RASTER (required)

Specify a raster from which to generate ROI statistics.

INPUT_ROI (required)

Specify an array of one or more ENVIROIs.

OUTPUT_REPORT_URI (optional)

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

Output Parameters

COVARIANCE

This is the covariance matrix, returned as an array: [number of bands, number of bands, number of ROIs].

MAX

This is the maximum data value, returned as an array: [number of bands, number of ROIs].

MEAN

This is the mean data value, returned as an array: [number of bands, number of ROIs].

MIN

This is the minimum data value, returned as an array: [number of bands, number of ROIs].

ROI_COLORS

This is an array of RGB triplets representing the ROI colors as defined by the ENVIROIs.

ROI_NAMES

This is an array of ROI names as defined by the input ENVIROIs.

ROI_PIXEL_COUNT

This is the number of pixels for each ROI, returned as an array: [number of ROIs].

STDDEV

This is the standard deviation, returned as an array: [number of bands, number of ROIs].

Methods

Execute

Parameter

ParameterNames

Properties

Version History

ENVI 5.4. 1	Introduced
ENVI 5.5.3	Added OUTPUT_REPORT_URI parameter