ArcMap

Decimate TIN Nodes

Available with 3D Analyst license.

Summary

Creates a triangulated irregular network (TIN) dataset using a subset of nodes from a source TIN.

Illustration

DecimateTinNodes illustration

Usage

  • This tool provides a form of generalization that is useful for thinning oversampled data and subsequently improving visualization. The following thinning options are provided:

    • Z Tolerance—Resulting TIN will maintain the vertical accuracy of its source TIN within the specified Z tolerance value, which is always expressed in the native Z-unit of the source TIN. The deviation of any node from the source TIN, when compared to the interpolated value of the output TIN, will not exceed the Z tolerance.
    • Count—Reduces the number of nodes in the output TIN to the specified value, which is presumedly less than the node count of the source TIN. Nodes are generally selected to maintain the extent and surface characteristics of the source TIN.

  • If the Copy Breaklines option is selected, breaklines in the source TIN will be stored in the output without any generalization. Nodes contributed by breaklines are not factored toward any maximum node count limit.

  • The data boundary of the resulting TIN will be enforced as breakline edges regardless of whether the option to copy breaklines has been used or even whether the input TIN data boundary is enforced with breakline edges. This may increase the size of the output TIN and operates independently of any specified maximum node count limit.

Syntax

arcpy.ddd.DecimateTinNodes(in_tin, out_tin, method, {copy_breaklines})
ParameterExplanationData Type
in_tin

The TIN dataset to process.

TIN Layer
out_tin

The TIN dataset that will be generated.

TIN
method
"ZTOLERANCE <z_tolerance_value> <max_node_value>" or "COUNT <max_node_value>"

Specifies the decimation method for selecting a subset of nodes from the input TIN.

  • ZTOLERANCE <z_tolerance_value> <max_node_value> — Generalizes TIN within a specified vertical accuracy. An optional node limit can also be specified. This parameter is supplied as a string, so "ZTOLERANCE 0.5 5500" would represent a Z-tolerance value of 0.5 and a max node value of 5,500.
  • COUNT <max_node_value> —Generalizes TIN by constraining its size to a specified node limit. This parameter is supplied as a string, so "COUNT 5500" would represent a maximum node count of 5,500.
Decimate
copy_breaklines
(Optional)

Indicates whether breaklines from the input TIN are copied over to the output.

  • BREAKLINES —Breaklines will be copied.
  • NO_BREAKLINES —Breaklines will not be copied. This is the default.
Boolean

Code sample

DecimateTinNodes 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.DecimateTinNodes_3d("tin", "tin_simple", "COUNT 5000" "BREAKLINES")
DecimateTinNodes example 2 (stand-alone script)

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

'''****************************************************************************
Name: DecimateTinNodes Example
Description: This script demonstrates how to use the 
             DecimateTinNodes tool.
****************************************************************************'''

# Import system modules
import arcpy
from arcpy import env

# Obtain a license for the ArcGIS 3D Analyst extension
arcpy.CheckOutExtension("3D")

# Set environment settings
env.workspace = "C:/data"

# Set Local Variables
inTin = "elevation"
method = "COUNT 5000"
copyBrk = "BREAKLINES"
# Ensure output name is unique
outTin = arcpy.CreateUniqueName("simple_elev")

#Execute DecimateTinNodes
arcpy.DecimateTinNodes_3d(inTin, outTin, method, copyBrk)

Environments

Licensing information

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

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