ArcMap

Change Terrain Reference Scale

Available with 3D Analyst license.

Summary

Changes the reference scale associated with a terrain pyramid level.

Usage

  • Consider changing a terrain pyramid's reference scale if you experience undesirable draw speed performance or require greater densification of data points in the pyramid's display scale range.

  • It may also be necessary to add or remove a pyramid level when changing the resolution of an existing one, which can be done by using Add Terrain Pyramid or Remove Terrain Pyramid.

  • When used in an SDE database, the input terrain cannot be registered as versioned.

Syntax

arcpy.ddd.ChangeTerrainReferenceScale(in_terrain, old_refscale, new_refscale)
ParameterExplanationData Type
in_terrain

The terrain dataset to process.

Terrain Layer
old_refscale

The reference scale of an existing pyramid level.

Long
new_refscale

The new reference scale for the pyramid level.

Long

Derived Output

NameExplanationData Type
derived_out_terrain

The updated terrain.

Terrain Layer

Code sample

ChangeTerrainReferenceScale 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.ChangeTerrainReferenceScale_3d('terrain.gdb/terrainFDS/terrain1', 
                                   1000, 2000)
ChangeTerrainReferenceScale example 2 (stand-alone script)

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

'''****************************************************************************
Name: Update Terrain
Description: This script demonstrates how to update a terrain dataset 
             with new elevation measurements obtained from Lidar by
             importing LAS files to multipoint features, then appending the
             new points to another multipoint feature that participates in a
             terrain. The terrain's pyramids are modified to optimize its 
             draw speed.
****************************************************************************'''
# Import system modules
import arcpy
from arcpy import env
import exceptions, sys, traceback

try:
    arcpy.CheckOutExtension("3D")
    
    # Set environment settings
    env.workspace = "C:/data"

    # Set Variables
    inTerrain = "sample.gdb/featuredataset/terrain"
    currentPts = "existing_points"
    lasFiles = ['las/NE_Philly.las',
                'las/NW_Philly.las']
    newPts = 'in_memory/update_pts'
    # Define spatial reference of LAS files using factory code
    # for NAD_1983_StatePlane_Pennsylvania_South
    lasSR = arcpy.SpatialReference()
    lasSR.factoryCode = 2272
    lasSR.create()
    
    arcpy.AddMessage("Converting LAS files to multipoint features...")
    arcpy.ddd.LASToMultipoint(lasFiles, newPts, 1.5, 2, 1, 
                              'INTENSITY', lasSR)
    
    arcpy.AddMessage("Appending LAS points to {0}..."\
                     .format(currentPts))
    arcpy.AppendTerrainPoints_3d(inTerrain, currentPts, newPts)
    
    arcpy.AddMessage("Changing terrain pyramid reference scales...")
    arcpy.ddd.ChangeTerrainReferenceScale(inTerrain, 1000, 500)
    arcpy.ddd.ChangeTerrainReferenceScale(inTerrain, 2500, 2000)
    
    arcpy.AddMessage("Adding terrain pyramid level...")
    arcpy.ddd.AddTerrainPyramidLevel(inTerrain, "", "4 4500")
    
    arcpy.AddMessage("Changing pyramid resolution bounds for breaklines...")
    arcpy.ChangeTerrainResolutionBounds_3d(inTerrain, "breaklines", 5, 4)
    
    arcpy.AddMessage("Building terrain...")
    arcpy.ddd.BuildTerrain(inTerrain)
    
    arcpy.AddMessage("Completed updates.")

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)

finally:
    arcpy.CheckInExtension("3D")

Environments

Licensing information

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

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