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Harris Geospatial / Docs Center / ENVI API / Crop Science / ENVIAgCrops::Hydrate

ENVIAgCrops::Hydrate

ENVIAgCrops::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. Refer to the ENVI Task Engine and ENVI Services Engine topics in ENVI Help.

See the ENVIHydrate topic in ENVI Help if you are creating a general IDL routine that will restore multiple object types.

This method is part of ENVI Crop Science, which requires a separate license and installation.

Example


This example counts the crops in a spectral index image of a citrus orchard. It creates an ENVIAgCrops object named outCrops.

; Start the application
e = ENVI(/HEADLESS)
 
; Open an input file
File = Filepath('CitrusOrthophoto.dat', $
  Subdir=['data','crop_science'], $
  Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
 
; Preprocess the image so that crops are bright
MTVIImage = ENVISpectralIndexRaster(Raster, 'MTVI')
 
; Count the crops and create an ENVIAgCrops object
outCrops = ENVIAgCropCount(MTVIImage, 2.0, 5.0, $
  GAUSSIAN_FACTOR = 0, $
  /INCLUDE_EDGES, $
  INTENSITY_THRESHOLD = 0.8, $
  NUMBER_OF_INCREMENTS = 4, $
  PERCENT_OVERLAP = 100.0)
 
; Retrieve the dehydrated hash
dehydratedForm = outCrops.Dehydrate()
Obj_Destroy, outCrops
 
; Restore the object
newOutCrops = ENVIAgCrops.Hydrate(dehydratedForm)
Print, newOutCrops, /IMPLIED_PRINT

Syntax


Result = ENVIAgCrops.Hydrate(DehydratedForm, ERROR=value)

Return Value


The result is a reference to a new object instance.

Arguments


DehydratedForm

Key

Description

factory

Required. A string value of ENVIAgCrops indicating what object type the hash represents.

url

Required. A uniform resource locator (URL) identifying an ENVIAgCrops crop center file. Example:

"url" : "/usr/local/harris/envi/mydata/cropCenters.json"

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 the Manage Errors topic in ENVI Help for more information on error handling.

Version History


1.0

Introduced

See Also


ENVIAgCrops, ENVIAgCrops::Dehydrate



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