CalculateGridDefinitionFromRasterUnion Task

This task returns a grid definition from an array of rasters whose spatial extent encompasses all of the rasters.

The output grid definition can be used as input to tasks such as BuildLayerStack, RegridRaster, and RegridRasterSeries.

Example

This example creates a grid definition that is based on the geometric union of two different spatial grids. The images in the two grids are available from our ENVI Tutorials web page. Click the API Gridding Examples link to download the .zip file to your machine, then unzip the files.

MODIS Land Surface Temperature (MOD11_L2) swath image from 07 March 2009, georeferenced to a UTM Zone 54 coordinate system using ENVI's Georeference MODIS tool, corrected for bowtie artifacts, spatially subsetted, and scaled by 0.02 so that the pixel values are in Kelvins.
Suomi NPP VIIRS Land Surface Temperature EDR image from 07 March 2014, georeferenced to a Geographic Lat/Lon (WGS-84) coordinate system, and spatially subsetted.

Since the first input raster is in a UTM Zone 54 coordinate system, that will be the coordinate system of the output grid definition.

; Start the application

e = ENVI()

; Open the MODIS LST raster

File1 =  'MODIS_LST_2009-03-07.dat'

MODISRaster = e.OpenRaster(File1)

; Open the Suomi NPP VIIRS LST raster

File2 = 'VIIRSLST2014-03-07.dat'

VIIRSRaster = e.OpenRaster(File2)

; Get the task from the catalog of ENVITasks

Task = ENVITask('CalculateGridDefinitionFromRasterUnion')

; Define inputs

Task.INPUT_RASTERS = [MODISRaster, VIIRSRaster]

; Run the task

Task.Execute

; Create a layer Stack

LayerTask = ENVITask('BuildLayerStack')

LayerTask.INPUT_RASTERS = [MODISRaster, VIIRSRaster]

LayerTask.GRID_DEFINITION = Task.OUTPUT_GRIDDEFINITION

LayerTask.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, LayerTask.OUTPUT_RASTER

; Display the result

View = e.GetView()

Layer = View.CreateLayer(LayerTask.OUTPUT_RASTER)

; Print the properties of the grid definition

Print, Task.OUTPUT_GRIDDEFINITION

Syntax

Result = ENVITask('CalculateGridDefinitionFromRasterUnion')

Input properties (Set, Get): INPUT_RASTERS, PIXEL_SIZE

Output properties (Get only): OUTPUT_GRIDDEFINITION

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:

COMMUTE_ON_DOWNSAMPLE

INPUT_RASTERS (required)

Specify an array of rasters from which to calculate the grid definition. The first raster will determine the coordinate system and pixel size of the grid definition, unless they are later modified.

OUTPUT_GRIDDEFINITION

This is a reference to the output ENVIGridDefinition.

PIXEL_SIZE (optional)

Specify a two-element array with the [x,y] pixel size of the output grid definition.

Version History

ENVI 5.5. 2

Introduced

API Version

4.2