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

ENVIGramSchmidtPanSharpeningTask

ENVIGramSchmidtPanSharpeningTask

This task performs Gram-Schmidt Pan Sharpening using a low-resolution raster and a high-resolution panchromatic raster.

If you process a spatial subset, the resulting image from this ENVITask may differ by approximately 2 percent, compared to one created using the ENVI user interface. The latter uses the full image for resampling, while the ENVITask uses only the subset for processing.

Example


; Start the application
e = ENVI()
 
; Open an input file
msi_file = Filepath('qb_boulder_msi', Subdir=['data'], $
  Root_Dir=e.Root_Dir)
msi_raster = e.OpenRaster(msi_file)
pan_file = Filepath('qb_boulder_pan', Subdir=['data'], $
  Root_Dir=e.Root_Dir)
pan_raster = e.OpenRaster(pan_file)
 
; Process a spatial subset
Subset = ENVISubsetRaster(msi_raster, Sub_Rect=[600,200,799,399])
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('GramSchmidtPanSharpening')
 
; Define inputs
Task.INPUT_LOW_RESOLUTION_RASTER = Subset
Task.INPUT_HIGH_RESOLUTION_RASTER = pan_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, jump to a specific
; coordinate, and flicker between the
; original and pan-sharpened images
View1 = e.GetView()
Layer1 = View1.CreateLayer(msi_raster)
Layer2 = View1.CreateLayer(Task.Output_Raster)
Layer2.QUICK_STRETCH='linear 2%'
Portal = View1.CreatePortal()
View1.GoToLocation,482221.6000, 4428141.2000, /Map
View1.Zoom, 2.0
Portal.Animate, 2.0, /FLICKER

Syntax


Result = ENVITask('GramSchmidtPanSharpening')

Input properties (Set, Get): IGNORE_VALIDATE, INPUT_LOW_RESOLUTION_RASTER, INPUT_HIGH_RESOLUTION_RASTER, OUTPUT_RASTER_URI, RESAMPLING, SENSOR

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.

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_HIGH_RESOLUTION_RASTER (required)

Specify a high-resolution panchromatic raster.

INPUT_LOW_RESOLUTION_RASTER (required)

Specify a low-resolution raster.

NAME

This property contains the name of the task.

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.

RESAMPLING (optional)

Specify the resampling method.

  • Nearest Neighbor: Uses the nearest pixel without any interpolation.
  • Bilinear (default): Performs a linear interpolation using four pixels to resample.
  • Cubic Convolution: Uses 16 pixels to approximate the sinc function using cubic polynomials to resample the image.

SENSOR (optional)

Specify a lower-case string that indicates the sensor that acquired the high-resolution panchromatic input. If SENSOR is not set, then the task determines if the data has valid sensor information in the metadata. If not, SENSOR is set to Unknown.

See the filterfuncs directory in the ENVI installation path for a list of valid sensor strings. User-defined sensors are also valid as long as they are in this directory. The default path varies by operating system.

Version History


ENVI 5.2

Introduced

API Version


3.1.0

See Also


ENVITask, ENVITask::Parameter, ENVISubsetRaster



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