This is a reference to an ENVIStretchParameters object, which defines the stretch type to apply to a single-band raster, along with its minimum and maximum values and percentages. This object is currently only used with topographic shading ENVITasks.
Example
See the code examples in the following task topics:
Syntax
Result = ENVIStretchParameters([Properties=value] [, ERROR=variable])
Arguments
None
Methods
Dehydrate
Hydrate
Properties
Properties marked as (Init) can be set during the initial creation of the object. Properties marked as (Get) can be retrieved. Properties marked as (Set) can be set after initial creation.
MAX_PERCENT (optional, Get, Set)
Specify a value from 0 to 100 indicating the maximum percentage of the histogram to include in the specified stretch. If you do not set this property, the default value will be 100 percent.
MAX_VALUE (optional, Get, Set)
Specify a double-precision floating point value indicating the maximum pixel value for the specified stretch. If you do not set this property, the default value will be NaN.
MIN_PERCENT (optional, Get, Set)
Specify a value from 0 to 100 indicating the minimum percentage of the histogram to include in the specified stretch. If you do not set this property, the default value will be 0 percent.
MIN_VALUE (optional, Get, Set)
Specify a double-precision floating point value indicating the minimum pixel value for the specified stretch. If you do not set this property, the default value will be NaN.
STRETCH_TYPE (optional, Get, Set)
Specify a string with the stretch type to apply. The following are valid strings:
- Equalization
- Gaussian
- Linear (default)
- Logarithmic
- Square Root
Keywords
ERROR (optional)
Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.
When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.
See Manage Errors for more information on error handling in ENVI programming.
Version History
API Version
4.2
See Also
TopographicShadingUsingHLS Task, TopographicShadingUsingHSV Task, TopographicShadingUsingRGB Task