DiceRasterByDistance Task

This task separates a raster into tiles based on a specified distance. In most cases the tiles in the last row and column will be smaller than the specified distance, as the following example shows:

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('DiceRasterByDistance')

; Define inputs

Task.INPUT_RASTER = Raster

Task.TILE_DISTANCE = 1000.

Task.DISTANCE_UNITS = 'Meters'

Task.TILE_GRID_VECTORS = 'true'

; Define the output directory

Task.OUTPUT_DIRECTORY = Filepath('', /TMP)

; Run the task

Task.Execute

; Get the collection of data objects currently in the Data Manager

DataColl = e.Data

; Add the output to the Data Manager

DataColl.Add, Task.OUTPUT_RASTER

; Display the results

View1 = e.GetView()

FOR i=0,N_Elements(Task.Output_Raster)-1 DO $

  Layer = View1.CreateLayer(Task.OUTPUT_RASTER[i])

vectorLayer = View1.CreateLayer(Task.OUTPUT_VECTOR)

View1.Zoom, /FULL_EXTENT

Syntax

Result = ENVITask('DiceRasterByDistance')

Input parameters (Set, Get): DISTANCE_UNITS, INPUT_RASTER, OUTPUT_DIRECTORY, TILE_DISTANCE, TILE_GRID_VECTORS

Output parameters (Get only): OUTPUT_RASTER, OUTPUT_VECTOR

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

DISTANCE_UNITS (required)

Specify a string indicating the units of the tile distance. The options are:

Meters
Km
Feet
US Survey Feet
Yards
Miles
Nautical Miles

INPUT_RASTER (required)

Specify the input raster. It must have an ENVIStandardRasterSpatialRef, ENVIRPCRasterSpatialRef, or ENVIPseudoRasterSpatialRef spatial reference defined.

OUTPUT_DIRECTORY (optional)

Specify the output directory for the tiles. If set to an asterisk (*), the output rasters will be virtual. This will not be written to disk, and the directory will not be created. If you do not set this parameter, the tiles will save to the directory indicated by the ENVI Output Directory preference.

TILE_DISTANCE (required)

Specify a double-precision value indicating the distance by which tiles are created, in the units specified by DISTANCE_UNITS. This value applies to both the X and Y direction.

TILE_GRID_VECTORS (optional)

Set this parameter to true to create an output shapefile that shows the tile boundaries.

Output Parameters

OUTPUT_RASTER

This parameter contains an array of output rasters. Their filenames contain the root name of the input raster with the row/column index appended in the form of RxCx. For example, R2C3 means row 2 and column 3.