CastRaster Task

This task creates an ENVIRaster from a source raster where pixel values have been cast to a specified data type; for example, unsigned integer or double-precision floating point.

The virtual raster associated with this task is ENVICastRaster.

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('CastRaster')

; Define inputs

Task.INPUT_RASTER = Raster

Task.DATA_TYPE = 'float'

; Run the task

Task.Execute

; Get the collection of objects currently in the Data Manager

DataColl = e.Data

; Add the output to the Data Manager

DataColl.Add, Task.OUTPUT_RASTER

; Display the result

View = e.GetView()

Layer = View.CreateLayer(Task.OUTPUT_RASTER)

Syntax

Result = ENVITask('CastRaster')

Input properties (Set, Get): DATA_IGNORE_VALUE, DATA_TYPE, INPUT_RASTER, OUTPUT_RASTER_URI

Output properties (Get only): 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:

Properties

This task inherits the following properties from ENVITask:

COMMUTE_ON_DOWNSAMPLE

DATA_IGNORE_VALUE (optional)

Specify a numeric pixel value that will be ignored upon export. The pixel state of the output raster will be the same as that of the input raster, regardless of whether or not it was set. The data ignore value should be different from any other pixel value in the input raster, in order to avoid masking out good pixels during export.

DATA_TYPE (required)

Specify a string indicating the data type to cast the pixel values to. Choose one of the following values, which are supported by any ENVIRaster:

byte: An 8-bit unsigned integer ranging in value from 0 to 255.
int: A 16-bit signed integer ranging from -32,768 to +32,767.
long: A 32-bit signed integer ranging in value from -2,147,483,648 to +2,147,483,647.
float: A 32-bit, single-precision, floating-point number in the range of ±10³⁸, with approximately six or seven significant digits.
double: A 64-bit, double-precision, floating-point number in the range of ±10³⁰⁸ with approximately 15 or 16 significant digits.
uint: A 16-bit unsigned integer ranging from 0 to 65,535.
ulong: A 32-bit unsigned integer ranging in value from 0 to 4,294,967,295.

Note: Casting a floating-point raster to integer will truncate the data values. Overflow will occur when the original value is greater than the maximum value for the output data type.

INPUT_RASTER (required)

Specify an input ENVIRaster.

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 to export the associated OUTPUT_RASTER.

If you set this property to an asterisk symbol (*), the output raster will be virtual and not written to disk.
If you do not specify this property, or set it to an exclamation symbol (!), a temporary file will be created.

Version History

ENVI 5.4. 1	Introduced
ENVI 5.5	OUTPUT_RASTER_URI now supports '*', which allows OUTPUT_RASTER to be virtual output.

API Version

4.2