ArcMap

Set LAS Class Codes Using Features

Summary

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

Usage

  • All LAS points that intersect with 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 would 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 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)

Syntax

arcpy.ddd.SetLasClassCodesUsingFeatures(in_las_dataset, feature_class, {compute_stats})
ParameterExplanationData 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, e.g. [['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 should 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, like classification codes and return information, to values that are present in the LAS file.

  • COMPUTE_STATS —Statistics will be computed.
  • NO_COMPUTE_STATS —Statistics will not be computed. This is the default.
Boolean

Derived Output

NameExplanationData 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.

import arcpy
from arcpy import env

arcpy.CheckOutExtension('3D')
env.workspace = 'C:/data'
arcpy.SetLasClassCodesUsingFeatures_3d("test.lasd", [["lake.shp 0 9"],
                                       ["outliers.shp", 5, "NO_CHANGE", 
                                        "NO_CHANGE", "NO_CHANGE", "SET"]], 
                                       "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
import exceptions, sys, traceback

try:
    arcpy.CheckOutExtension('3D')
    # 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"]])
    arcpy.CheckInExtension('3D')
except arcpy.ExecuteError:
    print arcpy.GetMessages()
except:
    # Get the traceback object
    tb = sys.exc_info()[2]
    tbinfo = traceback.format_tb(tb)[0]
    # Concatenate error information into message string
    pymsg = 'PYTHON ERRORS:\nTraceback info:\n{0}\nError Info:\n{1}'\
          .format(tbinfo, str(sys.exc_info()[1]))
    msgs = 'ArcPy ERRORS:\n {0}\n'.format(arcpy.GetMessages(2))
    # Return python error messages for script tool or Python Window
    arcpy.AddError(pymsg)
    arcpy.AddError(msgs)

Environments

Licensing information

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

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