ENVIVector::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.

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

; Start the application

e = ENVI(/HEADLESS)

; Create an ENVIVector from the shapefile data

file = FILEPATH('states.shp', $

SUBDIRECTORY=['examples', 'data'])

vector = e.OpenVector(file)

; Retrieve the dehydrated hash

dehydratedForm = vector.Dehydrate()

vector.close

; Restore the object

newVector = ENVIVector.Hydrate(dehydratedForm)

Print, newVector, /IMPLIED_PRINT

Syntax

Result = ENVIVector.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 `URLVector` indicating what object type the hash represents.
auxiliary_url	A string array containing the URLs for any auxiliary files associated with the vector file. This key is generated on output if auxiliary files exist. On input this key is ignored to allow ENVI::OpenVector to override various behaviors.
url	Required. A uniform resource locator (URL) identifying a vector file for use in ENVI processing. Example: "url" : "/usr/local/INSTALL_DIR/envi/data/natural_earth_vectors/airports.shp"
stanag filenames	A uniform resource locator (URL) identifying a string or an array of strings of STANAG 4676 Track Points files for use in ENVI.
record_type	Value is IDLffShape Entities (type table).

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
ENVI 5.6.2	Added stanag filenames key
ENVI 5.7	Added record_type key

API Version

4.2