Use the Hydrate static function method to create the object from its dehydrated form. The dehydrated form consists of a hash containing the object’s properties and values. The Hydrate and Dehydrate methods let you store the object state in memory and restore it later.
Representing an object as a hash is necessary for running ENVI analytics with the ENVI Task Engine.
See the ENVIHydrate function if you are creating a general IDL routine that will restore multiple object types.
For additional information, see What are Hydrate and Dehydrate routines used for?
Example
e = ENVI(/HEADLESS)
file = FILEPATH('qb_boulder_msi', ROOT_DIR=e.ROOT_DIR, $
SUBDIRECTORY = ['data'])
raster = e.OpenRaster(file)
stretchRaster = ENVIRootStretchRaster(raster, $
MIN=[138,154,92,52], MAX=[1492,2047,1785,1807], ROOT_INDEX=2.0)
dehydratedForm = stretchRaster.Dehydrate()
stretchRaster.close
newImage = ENVIRootStretchRaster.Hydrate(dehydratedForm)
Print, newImage, /IMPLIED_PRINT
Syntax
Result = ENVIRootStretchRaster.Hydrate(DehydratedForm, ERROR=value)
Return Value
The result is a reference to a new object instance of this virtual raster class.
Arguments
DehydratedForm
Key |
Description |
factory |
Required. A string value of RootStretchRaster indicating what object type the hash represents.
|
input_raster |
Required. The input ENVIRaster for use in ENVI processing.
Example:
"input_raster": {
"url": "/usr/local/INSTALL_DIR/envi/data/qb_boulder_msi",
"factory": "URLRaster"
}
|
min |
Required. Minimum value to be considered, also known as the "black point." If this value is a scalar, it applies to all bands. If it is an array, it must have the same number of elements as the input raster has bands. Example:
"min": [138, 154, 92, 52],
|
max |
Required. Maximum value to be considered, also known as the "white point." If the value is a scalar, it applies to all bands. If it is an array, it must have the same number of elements as the input raster has bands. Example:
"max": [1492, 2047, 1785, 1807],
|
brightness |
Integer value from 0 to 100, indicating the brightness level to display. The default value is 50 if no brightness is specified. You can also set this value to a scalar or an array with the same number of elements as the raster has bands. Example:
"brightness": [65, 75, 85, 95],
|
name |
A string that identifies the raster.
|
root_index |
The root index function applied to the stretch. For example, a value of 2.0 indicates a square root, and a 3.0 value indicates a cube root. If not specified, then 2.0 is the default. Example:
"root_index" : 3
|
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
4.3
See Also
ENVIRootStretchRaster, ENVIRootStretchRaster::Dehydrate, ENVIHydratable, ENVIHydrate