Change LAS Class Codes (3D Analyst)

Summary

Reassigns the classification codes and flags of .las files.

Usage

  • All .las files referenced by the LAS dataset will be evaluated by this tool, but only the files that contain the provided class codes will be modified.

  • Consider using this tool to update the classification of data points in .las files generated prior to the introduction of standardized class codes in the LAS 1.1 specifications.

  • ArcGIS uses the LAS classification scheme defined by the American Society for Photogrammetry and Remote Sensing (ASPRS). Learn more about lidar point classification.

    Classification Value Classification Type

    0

    Never Classified

    1

    Unassigned

    2

    Ground

    3

    Low Vegetation

    4

    Medium Vegetation

    5

    High Vegetation

    6

    Building

    7

    Low Noise

    8

    Model Key / Reserved

    9

    Water

    10

    Rail

    11

    Road Surface

    12

    Overlap / Reserved

    13

    Wire – Guard

    14

    Wire – Conductor

    15

    Transmission Tower

    16

    Wire – Connector

    17

    Bridge Deck

    18

    High Noise

    19 – 63

    Reserved for ASPRS Definition (LAS 1.1 to 1.3 support up to class code 31)

    32 – 255

    User Definable (Only supported in LAS 1.0 and certain versions of 1.4)

Parameters

LabelExplanationData Type
Input LAS Dataset

The LAS dataset to process.

LAS Dataset Layer
Class Codes

Specifies the list of existing class codes to be modified and the change that will be made to its respective classification code value and classification flags.

Value Table
Compute statistics
(Optional)

Specifies whether statistics will be computed for the .las files referenced by the LAS dataset. Computing statistics provides a spatial index for each .las file, which improves analysis and display performance. Statistics also enhance the filtering and symbology experience by limiting the display of LAS attributes, such as classification codes and return information, to values that are present in the .las file.

  • Checked—Statistics will be computed. This is the default.
  • Unchecked—Statistics will not be computed.
Boolean
Processing Extent
(Optional)

The extent of the data that will be evaluated.

  • Default—The extent will be based on the maximum extent of all participating inputs. This is the default.
  • Union of Inputs—The extent will be based on the maximum extent of all inputs.
  • Intersection of Inputs—The extent will be based on the minimum area common to all inputs.
  • Current Display Extent—The extent is equal to the visible display. The option is not available when there is no active map.
  • As Specified Below—The extent will be based on the minimum and maximum extent values specified.
  • Browse—The extent will be based on an existing dataset.
Extent
Processing Boundary

A polygon feature that defines the area of interest to be processed.

Feature Layer
Process entire LAS files that intersect extent
(Optional)

Specifies how the area of interest will be used in determining how .las files will be processed. The area of interest is defined by the Processing Extent parameter value, the Processing Boundary parameter value, or a combination of both.

  • Unchecked—Only LAS points that intersect the area of interest will be processed. This is the default.
  • Checked—If any portion of a .las file intersects the area of interest, all the points in that .las file, including those outside the area of interest, will be processed.
Boolean
Update pyramid
(Optional)

Specifies whether the LAS dataset pyramid will be updated after the class codes are modified.

  • Checked—The LAS dataset pyramid will be updated. This is the default.
  • Unchecked—The LAS dataset pyramid will not be updated.
Boolean

Derived Output

LabelExplanationData Type
Output LAS Dataset

The updated LAS dataset.

LAS Dataset Layer

arcpy.ddd.ChangeLasClassCodes(in_las_dataset, class_codes, {compute_stats}, {extent}, boundary, {process_entire_files}, {update_pyramid})
NameExplanationData Type
in_las_dataset

The LAS dataset to process.

LAS Dataset Layer
class_codes
[[current_class, new_class],...]

Specifies the list of existing class codes to be modified and the change that will be made to its respective classification code value and classification flags.

The existing class code, the new class code, and the new class flag can be represented as a space-delimited string or a list of lists containing the values to be reclassified. For example, a current class code of 5 can be changed to 25 by specifying "5 2" or [[5, 2]]. Likewise, a change to the synthetic class flag can be made by adding the keyword for the desired modification ("5 2 SET" or [[5, 2, "SET"]]). Multiple changes can be specified as a semicolon-delimited string (for example, "5 2; 8 3; 1 4") or as a list of lists (for example, [[5, 2], [8, 3], [1, 4]]).

Value Table
compute_stats
(Optional)

Specifies whether statistics will be computed for the .las files referenced by the LAS dataset. Computing statistics provides a spatial index for each .las file, which improves analysis and display performance. Statistics also enhance the filtering and symbology experience by limiting the display of LAS attributes, such as classification codes and return information, to values that are present in the .las file.

  • COMPUTE_STATSStatistics will be computed. This is the default.
  • NO_COMPUTE_STATSStatistics will not be computed.
Boolean
extent
(Optional)

The extent of the data that will be evaluated.

  • MAXOF—The maximum extent of all inputs will be used.
  • MINOF—The minimum area common to all inputs will be used.
  • DISPLAY—The extent is equal to the visible display.
  • Layer name—The extent of the specified layer will be used.
  • Extent object—The extent of the specified object will be used.
  • Space delimited string of coordinates—The extent of the specified string will be used. Coordinates are expressed in the order of x-min, y-min, x-max, y-max.
Extent
boundary

A polygon feature that defines the area of interest to be processed.

Feature Layer
process_entire_files
(Optional)

Specifies how the processing extent will be applied.

  • PROCESS_EXTENTOnly LAS points that intersect the area of interest will be processed. This is the default.
  • PROCESS_ENTIRE_FILESIf any portion of a .las file intersects the area of interest, all the points in that .las file, including those outside the area of interest, will be processed.
Boolean
update_pyramid
(Optional)

Specifies whether the LAS dataset pyramid will be updated after the class codes are modified.

  • UPDATE_PYRAMIDThe LAS dataset pyramid will be updated. This is the default.
  • NO_UPDATE_PYRAMIDThe LAS dataset pyramid will not be updated.
Boolean

Derived Output

NameExplanationData Type
derived_las_dataset

The updated LAS dataset.

LAS Dataset Layer

Code sample

ChangeLasClassCodes example 1 (Python window)

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

arcpy.env.workspace = 'C:/data'
arcpy.ddd.ChangeLasClassCodes('test.lasd', [[5, 2], [3, 1], [4, 6]],
                           'COMPUTE_STATS')
ChangeLasClassCodes example 2 (stand-alone script)

The following sample demonstrates the use of this tool in a stand-alone Python script.

'''****************************************************************************
Name: Update LAS 1.0 Classification to ASPRS 1.1 Specs
Description: Updates classification of version 1.0 LAS files to conform to
             the standardized class codes introduced in the 1.1 specifications.
             The code is designed for use as a script tool.
****************************************************************************'''
# Import system modules
import arcpy

# Set Local Variables
inLas = arcpy.GetParameterAsText(0)
recursion = arcpy.GetParameterAsText(1)
lasd = arcpy.GetParameterAsText(2)
reclassList = arcpy.GetParameterAsText(3) #List of values '<oldCode> <newCode>'
calcStats = arcpy.GetParameter(4)

# Execute CreateLasDataset
arcpy.management.CreateLasDataset(inLas, lasd, recursion)
# Execute ChangeLasClassCodes
arcpy.ddd.ChangeLasClassCodes(lasd, reclassList, calcStats)

Licensing information

  • Basic: Requires 3D Analyst
  • Standard: Requires 3D Analyst
  • Advanced: Requires 3D Analyst

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