QuerySpectralIndices Task
This task returns a string array of the spectral indices that can be computed for a given input raster, based on its wavelength metadata. Issue the PRINT command on the AVAILABLE_INDICES property (see code example) or open the Data Manager in the user interface to see the list of available indices.
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)
; Get the task from the catalog of ENVITasks
Task = ENVITask('QuerySpectralIndices')
; Define inputs
Task.INPUT_RASTER = Raster
; Run the task
Task.Execute
; Get the task from the catalog of ENVITasks
Task2 = ENVITask('SpectralIndices')
; Define inputs
Task2.INPUT_RASTER = Raster
Task2.INDEX = Task.AVAILABLE_INDICES
; Run the task
Task2.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, Task2.OUTPUT_RASTER
; Display the result
View = e.GetView()
Layer = View.CreateLayer(Task2.OUTPUT_RASTER)
; Print the available indices to the
; ENVI command line
Print, Task.AVAILABLE_INDICES
Syntax
Result = ENVITask('QuerySpectralIndices')
Input properties (Set, Get): INPUT_RASTER
Output properties (Get only): AVAILABLE_INDICES
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:
This task also contains the following properties:
AVAILABLE_INDICES
A string array with the spectral indices that can be computed for the input raster.
INPUT_RASTER (required)
Specify a raster to query for available spectral indices.
Version History
ENVI 5.2 |
Introduced |
API Version
4.2
See Also
ENVITask, ENVISpectralIndexRaster, SpectralIndex Task, SpectralIndices Task, ENVISubsetRaster