E3De::CreateLidarFromSubrect

The CreateLidarFromSubrect method allows the user to create a spatial subset of a LiDAR dataset. This can be useful when only a certain area of the dataset is required for processing. Another useful scenario is to split the dataset up for distributed processing; for example, using the ENVI Services Engine (ESE).

This method has been deprecated. Use the CreatePointCloudSubProject task instead.

Example

The following example opens a LAS file and creates a spatial subset.

; Create a headless instance

e = E3De(/HEADLESS)

; Open a las file

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

  SUBDIRECTORY = ['DataSample'])

lidar = e.OpenLidar(file)

; Print number of points and extents

print, lidar.Total_Number_Of_Points

print, lidar.Data_Range

dataRange = lidar.Data_Range

dataRangeX = dataRange[3] - dataRange[0]

dataRangeY = dataRange[4] - dataRange[1]

subRect = [dataRange[0], dataRange[1], dataRange[0] + (dataRangeX * 0.5), dataRange[1] + (dataRangeY * 0.5)]

e.CreateLidarFromSubrect, lidar, 'C:\DataSampleSubset\DataSampleSubset.ini', subRect

; only one dataset open at a time

lidar.Close

subsetLidar = e.OpenLidar('C:\DataSampleSubset\DataSampleSubset.ini')

print, subsetLidar.Data_Range

Syntax

E3De.CreateLidarFromSubrect(E3dlidar, URI, SubRect [, ERROR=variable] [, SPATIALREF=E3DLidarspatialref])

Arguments

E3dlidar

The E3DLidar object from which to generate the subrectangle. If this E3DLidar was opened with DIRECT_READ set then an error will be thrown.

URI

A scalar string that is a fully-qualified path and name of the new LiDAR subrectangle .ini file.

SubRect

A 4x1 array, [xMin, yMin, xMax, yMax], specifying the spatial subrectangle of the new LiDAR object.

If the sub rect dimensions are smaller than the 32x32 meter native tile boundary, then the subrectangle dimensions are scaled up to the native tile boundary.

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.

SPATIALREF

An instance of an E3DLidarSpatialRef. Use this keyword to specify the coordinate system of the subrectangle. If no SPATIALREF is supplied, UTM WGS84 is assumed.

Version History

3.2 SP1	Introduced
ENVI 5.3	Obsolete