Build LAS Dataset Pyramid (Data Management)

Summary

Constructs or updates a LAS dataset display cache, which optimizes its rendering performance.

Usage

• The LAS dataset pyramid is stored in the same location as the LAS dataset: in a directory whose name begins with the name of the LAS dataset and ends with .slas. The pyramid typically occupies one-third of the overall size of the .las files referenced by the LAS dataset and is composed of multiple levels of progressively thinned LAS points. The points participating in each level are determined by binning the space where the points exist and selecting one point in each binned region using the point selection method.

• The construction of the LAS dataset pyramid maximizes the use of available memory resources to speed up the operation. When a sufficient amount of RAM is not available, the required memory will be paged to disk. If possible, try to maximize free memory by exiting any unnecessary application prior to executing this tool.

• Temporary files that are approximately equal to half the size of the .las files or the uncompressed size of the .zlas files will be generated in the scratch workspace. Ensure that the scratch workspace is set to a location with a sufficient amount of storage space.

• A LAS dataset with a pyramid includes a new schema that is not supported in ArcGIS Desktop or in ArcGIS Pro releases prior to 2.6. If the LAS dataset is actively used in those applications, consider creating a duplicate of the LAS dataset using the Copy tool. Then build the pyramid on the duplicate dataset. The same .las files can be referenced by both LAS datasets. If the pyramids have already been built and the .las files need to be used in applications that do not support the pyramid, use the Create LAS Dataset tool to create a LAS dataset that references the same files. You don't need another copy of the source .las files; you need another LAS dataset with no pyramid.

• This tool can be used to update an out-dated LAS dataset pyramid. The pyramid can become outdated by any of the following:

  • The addition of new .las or .zlas file references to the LAS dataset.
  • The removal of existing .las or .zlas file references from the LAS dataset.
  • Classification updates made through geoprocessing tools that were executed without specifying the option for updating the LAS dataset pyramid. When performing a series of .las classification edits through multiple geoprocessing tools, consider using the option to update the LAS dataset pyramid on the final tool that will be run.

• Once the LAS dataset pyramid has been constructed, the point selection method cannot be changed. To use a different point selection method, the existing pyramid must be deleted. This can be done by using the Remove Files From LAS Dataset tool or from the Pyramid tab on the LAS Dataset Properties dialog box. To access the LAS Dataset Properties dialog box, right-click the LAS dataset in the Catalog pane or the Catalog view and select the Properties option.

Parameters

Dialog

Label	Explanation	Data Type
Input LAS Dataset	The LAS dataset to process.	LAS Dataset Layer
Point Selection Method (Optional)	Specifies how the point in each binned region will be selected to construct the pyramid. This parameter is disabled if the LAS dataset contains a pyramid. Lowest Point—The point with the lowest z-value will be selected. Highest Point—The point with the highest z-value will be selected. Closest to Center—The point that is closest to the center of the binned region will be selected. Class Codes and Weights—The point with the highest weight value will be selected.	String
Input Class Codes and Weights (Optional)	The weights assigned to each class code that determine which points are retained in each thinning region. This parameter is only enabled when the Class Code Weights option is specified in the Point Selection Method parameter. The class code with the highest weight will be retained in the thinning region. If two class codes with the same weight exist in a given thinning region, the class code with the smallest point source ID will be retained.	Value Table

Derived Output

Label	Explanation	Data Type
Output LAS Dataset	The updated LAS dataset.	LAS Dataset Layer

Python

arcpy.management.BuildLasDatasetPyramid(in_las_dataset, {point_selection_method}, {class_codes_weights})

Name	Explanation	Data Type
in_las_dataset	The LAS dataset to process.	LAS Dataset Layer
point_selection_method (Optional)	Specifies how the point in each binned region will be selected to construct the pyramid. This parameter is disabled if the LAS dataset contains a pyramid. Z_MIN—The point with the lowest z-value will be selected. Z_MAX—The point with the highest z-value will be selected. CLOSEST_TO_CENTER—The point that is closest to the center of the binned region will be selected. CLASS_CODE—The point with the highest weight value will be selected.	String
class_codes_weights [class_codes_weights,...] (Optional)	The weights assigned to each class code that determine which points are retained in each thinning region. This parameter is only enabled when the Class Code Weights option is specified in the Point Selection Method parameter. The class code with the highest weight will be retained in the thinning region. If two class codes with the same weight exist in a given thinning region, the class code with the smallest point source ID will be retained.	Value Table

Derived Output

Name	Explanation	Data Type
derived_las_dataset	The updated LAS dataset.	LAS Dataset Layer

Code sample

BuildLasDatasetPyramid example (Python window)

The following sample demonstrates the use of this tool in the Python window.

import arcpy
arcpy.env.workspace = 'C:/data'
arcpy.ddd.BuildLasDatasetPyramid('test.lasd', 'MIN_Z')

Environments

Current Workspace, Scratch Workspace

Licensing information

• Basic: Requires 3D Analyst or Spatial Analyst
• Standard: Yes
• Advanced: Yes