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ENVICoordSys::Hydrate

ENVICoordSys::Hydrate

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 and the ENVI Services Engine.

See the ENVIHydrate function if you are creating a general IDL routine that will restore multiple object types.

Example


; Start the application
e = ENVI(/HEADLESS)
 
; Create an ENVICoordSys object
CoordSys = ENVICoordSys(COORD_SYS_CODE=20354)
 
; Retrieve the dehydrated hash
dehydratedForm = CoordSys.Dehydrate()
CoordSys.close
 
; Restore the object
newCoordSys = ENVICoordSys.Hydrate(dehydratedForm)
Print, newCoordSys, /IMPLIED_PRINT

Syntax


Result = ENVICoordSys.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 CoordSys indicating what object type the hash represents.

coord_sys_code

An integer indicating the geographic or projected coordinate system code to use. The coord_sys_code and coord_sys_string keys are mutually exclusive. Example:

"coord_sys_code" : 20354

coord_sys_str

A string indicating the geographic or projected coordinate system string. The coord_sys_code and coord_sys_string keys are mutually exclusive. Example:

"coord_sys_string" : 
"PROJCS["AGD_1984_AMG_Zone_54",
GEOGCS["GCS_Australian_1984",
DATUM["D_Australian_1984",
SPHEROID["Australian",6378160.0,298.25]],
PRIMEM["Greenwich",0.0],
UNIT["Degree",0.0174532925199433]],
PROJECTION["Transverse_Mercator"],
PARAMETER["False_Easting",500000.0],
PARAMETER["False_Northing",10000000.0],
PARAMETER["Central_Meridian",141.0],
PARAMETER["Scale_Factor",0.9996],
PARAMETER["Latitude_Of_Origin",0.0],
UNIT["Meter",1.0]]"

For a full list of coordinate system strings and codes, refer to the following text files in the \IDLxx\resource\pedata\predefined directory of the ENVI distribution:

  • EnviPEProjcsStrings.txt: PROJCS codes and strings
  • EnviPEGeogcsStrings.txt: GEOGCS codes and strings

Keywords


ERROR

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


ENVI 5.4

Introduced

API Version


3.3

See Also


ENVICoordSys, ENVICoordSys::Dehydrate, ENVIHydratable, ENVIHydrate



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