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

The virtual raster associated with this task is ENVIGainOffsetRaster.

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
 
; 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
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)

Syntax


Result = ENVITask('ApplyGainOffset')

Input parameters (Set, Get): GAIN, INPUT_RASTER, OFFSET, OUTPUT_RASTER_URI

Output parameters (Get only): OUTPUT_RASTER

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


GAIN (required)

Specify the data gain values that will be applied to the raster. If the array contains a single value, it is applied to all bands. Otherwise, it must contain the same number of elements as there are bands in the input raster.

INPUT_RASTER (required)

Specify the raster to apply the gain and offset.

OFFSET (required)

Specify the data offset values that will be applied to the raster. If the array contains a single value, it is applied to all bands. Otherwise, it must contain the same number of elements as there are bands in the input raster.

OUTPUT_RASTER_URI (optional)

Specify a string with the fully qualified filename and path to export the associated OUTPUT_RASTER.

  • If you set this parameter to an asterisk symbol (*), the output raster will be virtual and not written to disk.
  • If you do not specify this parameter, or set it to an exclamation symbol (!), a temporary file will be created.
  • If you set it to the hash symbol (#), ENVI creates a file in the temporary directory, but this file will not be deleted when ENVI closes.

Output Parameters


OUTPUT_RASTER

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

Methods


Execute

Parameter

ParameterNames

Properties


DESCRIPTION

DISPLAY_NAME

NAME

REVISION

TAGS

Version History


ENVI 5.2.1

Introduced

ENVI 5.5

OUTPUT_RASTER_URI now supports '*', which allows OUTPUT_RASTER to be virtual output.

See Also


ENVITask, ENVISubsetRaster, ENVIGainOffsetRaster, Masking Support in ENVITasks