Set LAS Class Codes Using Features (3D Analyst)

Summary

Classifies LAS points that intersect the two-dimensional extent of input features.

Usage

• All LAS points that intersect the two-dimensional extent of the input points, lines, and polygons, along with any buffers that may be applied, will be reclassified. If the three-dimensional distance from 3D features is required for reclassifying the LAS points, consider using the Locate LAS Points By Proximity tool.

• The buffer distance is particularly important for points and lines, since it is less likely that a given LAS point will fall exactly on the line or have the same coordinate as the input point. The distance units applied for the buffer are based on the linear units of the LAS dataset's spatial reference.

• If the LAS dataset layer's points have been filtered, only the filtered points that intersect the input features will be reclassified. The LAS dataset layer can filter using any combination of classification codes, classification flags, and return values through the Layer Properties dialog box or the Make LAS Dataset Layer tool.

• The LAS format supports the classification of each point based on the specifications defined by the American Society for Photogrammetry and Remote Sensing (ASPRS). The ArcGIS platform applies the classification scheme specified for LAS format file version 1.4:

  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)

  Note:

  While the bulk of class code assignments introduced with LAS 1.4 were previously designated as Reserved, class codes 8 and 12 were changed from Model Key and Overlap, respectively, to Reserved.

Parameters

Dialog

Label	Explanation	Data Type
Input LAS Dataset	The LAS dataset to process.	LAS Dataset Layer
Input Feature Class	One or more input features that will be used to define class code values for the lidar files referenced by the LAS dataset. The classification flag options default to No change but can be assigned by choosing Set or removed by choosing Clear. Each feature has the following options: Features—The features used for reclassifying LAS points. Buffer Distance—The distance that input features are buffered by prior to determining the LAS points that intersect the buffered area. New Class—The class code to be assigned. Synthetic—The Synthetic classification flag is used to identify points that were not obtained from a lidar sensor but were included in the .las file, such as survey control points that may not have been captured by the lidar sensor. KeyPoint—The Model Key Point classification flag represents a subset of points that are required to capture a particular level of detail in the lidar collection. Historically, this flag was associated with representing thinned ground points within a specific z-tolerance. Withheld—The Withheld classification flag signifies erroneous data that should be excluded from analysis and visualization. Overlap—The Overlap designation identifies points from overlapping scans and is only supported in LAS 1.4 files.	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
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

Label	Explanation	Data Type
Updated Input LAS Dataset	The updated LAS dataset.	LAS Dataset Layer

Python

arcpy.ddd.SetLasClassCodesUsingFeatures(in_las_dataset, feature_class, {compute_stats}, {update_pyramid})

Name	Explanation	Data Type
in_las_dataset	The LAS dataset to process.	LAS Dataset Layer
feature_class [[features, buffer_distance, new_class, synthetic, key_point, withheld, overlap],...]	Enter each feature and its associated options that will be used to define the classification operation as a list of lists, for example, [['feature1', 6, 9, 'NO_CHANGE', 'SET', 'CLEAR', 'NO_CHANGE'], ['feature 2', 0, 6, 'NO_CHANGE', 'NO_CHANGE', 'NO_CHANGE', 'NO_CHANGE']]. Each feature has the following options: features—The features used for reclassifying LAS points. buffer_distance—The buffer distance applied to the input features prior to determining the LAS points that intersect its area. new_class—The class code to be assigned. synthetic—The Synthetic classification flag is used to identify points that were not obtained from a lidar sensor. key_point—The Model Key Point classification flag represents a subset of points that can be used to capture a desired level of detail of a given class code. withheld—The Withheld classification flag signifies erroneous data that should be excluded from analysis and visualization. overlap—The Overlap designation identifies points from overlapping scans and is only supported in LAS 1.4 files.	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_STATS—Statistics will be computed. This is the default. NO_COMPUTE_STATS—Statistics will not be computed.	Boolean
update_pyramid (Optional)	Specifies whether the LAS dataset pyramid will be updated after the class codes are modified. UPDATE_PYRAMID—The LAS dataset pyramid will be updated. This is the default. NO_UPDATE_PYRAMID—The LAS dataset pyramid will not be updated.	Boolean

Derived Output

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

Code sample

SetLasClassCodesUsingFeatures example 1 (Python window)

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

arcpy.env.workspace = 'C:/data'
arcpy.SetLasClassCodesUsingFeatures_3d("test.lasd", ["lake.shp", 0, 9],
                                       compute_stats="COMPUTE_STATS")

SetLasClassCodesUsingFeatures example 2 (stand-alone script)

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

'''**********************************************************************
Name: Assign Withheld Classification Flag to Outlier Points in LAS Files
Description: Uses Locate Outliers to identify points in LAS files that
             should be assigned the 'withheld' classification flag.
             Designed for use as a script tool.
**********************************************************************'''
# Import system modules
import arcpy

# Set Local Variables
lasD = arcpy.GetParameterAsText(0)
outliers = 'in_memory/outliers'

# Execute LocateOutliers
arcpy.ddd.LocateOutliers(lasD, outliers, 'APPLY_HARD_LIMIT', -10,
                         350, 'APPLY_COMPARISON_FILTER', 1.2, 120,
                         0.8, 8000)

# Execute SetLasClassCodeUsingFeatures
arcpy.ddd.SetLasClassCodesUsingFeatures(lasd, [["outliers.shp", 5,
                                                "NO_CHANGE", "NO_CHANGE",
                                                "NO_CHANGE", "SET"]])

Environments

Current Workspace, Extent, Geographic Transformations

Licensing information

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