This task subsets a raster spatially (by geographic location) and/or spectrally.
Example
e = ENVI()
File = Filepath('qb_boulder_msi', Subdir=['data'], $
Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
subRect = [Raster.nSamples/4, Raster.nLines/4, $
Raster.nSamples*3/4, Raster.nLines*3/4]
SpatialRef = Raster.SPATIALREF
SpatialRef.ConvertFileToMap, subRect[0], subRect[1], ULx, ULy
SpatialRef.ConvertFileToMap, subRect[0], subRect[3], LLx, LLy
SpatialRef.ConvertFileToMap, subRect[2], subRect[1], URx, URy
SpatialRef.ConvertFileToMap, subRect[2], subRect[3], LRx, LRy
geoRect = [ LLx, LLy, URx, URy ]
Task = ENVITask('GeographicSubsetRaster')
Task.INPUT_RASTER = Raster
Task.SUB_RECT = geoRect
Task.Execute
DataColl = e.Data
DataColl.Add, Task.OUTPUT_RASTER
View = e.GetView()
Layer1 = View.CreateLayer(Task.OUTPUT_RASTER)
Syntax
Result = ENVITask('GeographicSubsetRaster')
Input parameters (Set, Get): BANDS, INPUT_RASTER, OUTPUT_RASTER_URI, SPATIAL_REFERENCE, SUB_RECT
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
BANDS (optional)
Specify an array of band indices to include in the OUTPUT_RASTER. The indices are zero-based, and a scalar is allowed for single-band output.
INPUT_RASTER (required)
Specify the input ENVIRaster to subset.
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.
SPATIAL_REFERENCE (optional)
Specify an ENVIPseudoRasterSpatialRef, ENVIRPCRasterSpatialRef, or ENVIStandardRasterSpatialRef object that indicates the spatial reference of the spatial subset. If you do not specify this parameter, ENVI will use the spatial reference of the input raster by default.
SUB_RECT (required)
Set this parameter to a four-element array expressing the spatial range of the raster data. The array is of the form [minX, minY, maxX, maxY]
Values can be map coordinates (x=eastings, y=northings) or geographic coordinates (x=longitude, y=latitude), depending on the spatial reference object used.
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, SubsetRaster Task, ENVISubsetRaster, Masking Support in ENVITasks