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Harris Geospatial / Docs Center / ENVI API / Processing / ApplyGainOffset

ApplyGainOffset

ENVIApplyGainOffsetTask

This task applies custom gain and offset values to each band of a raster, updating the pixel values accordingly. The output raster can be used for a custom calibration routine.

This task is different from ENVIRadiometricCalibrationTask, which applies gains and offsets automatically to common data types such as Worldview and Landsat. It then calibrates the data to radiance or reflectance.

Example


; Start the application
e = ENVI()
 
; Open an input file
File = Filepath('bhtmref.img', $
  Subdir=['classic', 'data'], Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('ApplyGainOffset')
 
; Define inputs
Task.GAIN = [2.00, 1.33, 1.20, 1.11, 2.60, 3.12]
Task.OFFSET = [12.33, 1.10, 6.00, 1.55, 5.32, 4.05]
Task.INPUT_RASTER = Raster
 
; Define outputs
Task.OUTPUT_RASTER_URI = e.GetTemporaryFilename()
 
; Run the task
Task.Execute
 
; Get the collection of data objects currently available in the Data Manager
DataColl = e.Data
 
; Add the output to the Data Manager
DataColl.Add, Task.Output_Raster
 
; Display the result
View1 = e.GetView()
Layer1 = View1.CreateLayer(Task.Output_Raster)

Syntax


Result = ENVITask('ApplyGainOffset')

Input properties (Set, Get): GAIN, IGNORE_VALIDATE, INPUT_RASTER, OFFSET, OUTPUT_RASTER_URI

Output properties (Get only): DESCRIPTION, NAME, OUTPUT_RASTER

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:

AddParameter

Execute

Parameter

ParameterNames

RemoveParameter

Properties


DESCRIPTION

This property describes the task.

GAIN (required)

Specify a floating-point array of data gain values, one per band, to apply to the input raster.

IGNORE_VALIDATE (optional)

This property is now deprecated and has no effect on task behavior. All task property values are validated when they are set, and they throw an error with bad input.

INPUT_RASTER (required)

Specify the raster to apply the gain and offset.

NAME

This property contains the name of the task.

OFFSET (required)

Specify a floating-point array of data offset values, one per band, to apply to the input raster.

OUTPUT_RASTER

This is a reference to the output raster of filetype ENVI.

OUTPUT_RASTER_URI (optional)

Specify a string with the fully qualified filename and path of the output raster. If you do not specify this property, the output raster is only temporary. Once the raster has no remaining references, ENVI deletes the temporary file.

Version History


ENVI 5.2, Service Pack 1

Introduced

API Version


3.1.0

See Also


ENVITask, ENVITask::Parameter, ENVISubsetRaster, ENVIGainOffsetRaster



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