ENVIPointCloud::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)

; Open a las file

file = FILEPATH('DataSample.las', ROOT_DIR=e.ROOT_DIR, $

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

pointcloud = e.OpenPointCloud(file, $

  PROJECT_URI=Filepath('DataSample', /TMP))

; Retrieve the dehydrated hash

dehydratedForm = pointcloud.Dehydrate()

pointcloud.close

; Restore the object

newPointCloud = ENVIPointCloud.Hydrate(dehydratedForm)

Print, newPointCloud, /IMPLIED_PRINT

Syntax

Result = ENVIPointCloud.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 URLPointCloud indicating what object type the hash represents.
url	Required. A fully qualified filename to be written, including the .las extension. Example: "url": "C:\\Program Files\\INSTALL_DIR\\envixx\\data\\lidar\\DataSample.las"
auxiliary_url	A string array containing the URLs for the ENVIPointCloud project files. This key is generated on output if auxiliary files exist. On input this key is ignored to allow ENVI::OpenPointCloud to override various behaviors.
project_uri	A string containing the path to the directory that contains the ENVIPointCloud's project files. Example: "project_uri": "C:\\lidar\\DataSample"
spatialref	An ENVIPointCloudSpatialRef object that indicates the coordinate system written to the .las file. Example: "spatialref": { "factory": "PointCloudSpatialRef", "coord_sys_code": 2236" } See ENVIPointCloudSpatialRef::Dehydrate for more information.
txt_format	Specify the columns for text format point datasets. This is a 1-D array of strings were each entry in the array details the column type. The supported strings are: x, y, height, intensity, red, green, blue, ignore. Example: "txt_format": ["x", "y", "height"]
txt_skip_header_lines	Specify how many lines to skip from the beginning of the text file to get to the first point. Example: "txt_skip_header_lines": 3

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 5.5	Added auxiliary_url key to the hash that is returned.

API Version

4.2