ArcGIS Help 10.1 - Delineate TIN Data Area (3D Analyst)

Summary

Redefines the data area, or interpolation zone, of a triangulated irregular network (TIN) based on its triangle edge length.

Illustration

Usage

The source TIN will be modified by this tool. If you prefer not to modify the input, consider creating a duplicate dataset using the Copy TIN tool.
All triangles are marked as inside before edge length classification begins. This will effectively undo any preexisting data area classification. If the result obtained from one iteration is unsatisfactory, the tool can be executed again without having to obtain the original data.
Extreme edge lengths produced by concave characteristics in the TIN's source measurements can be removed from the TIN's valid data area through this tool. Triangles that have an edge exceeding the Maximum Edge Length will be masked as NoData areas.
Note:
The Maximum Edge Length value is best determined from the average spacing of nodes in the TIN within areas that are considered valid data zones. Provide a value that is larger than the average spacing. The most successful use of this tool is based on knowledge of the data used to create the TIN.
The Method determines which triangles are evaluated.
Note:
Use PERIMETER_ONLY if the concave data portions are relegated to the outer extremities of the TIN.

Syntax

DelineateTinDataArea_3d (in_tin, max_edge_length, {method})

Parameter	Explanation	Data Type
in_tin	The input TIN.	TIN Layer
max_edge_length	The two-dimensional distance that defines the maximum length of a TIN triangle edge in the TIN's data area. Triangles with one or more edges that exceed this value will be considered outside the TIN's interpolation zone and will not be rendered in maps or used in surface analysis.	Double
method (Optional)	The method used for delineating the TIN's data area. PERIMETER_ONLY —Iterates through triangles from the TIN's outer extent inward and will stop when the current iteration of boundary triangle edges does not exceed the Maximum Edge Length. This is the default. ALL —Classifies the entire collection of TIN triangles by edge length.	String

Code Sample

DelineateTinDataArea 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.DelineateTinDataArea_3d("elevation", 10, "PERIMETER_ONLY")

DelineateTinDataArea example 2 (stand-alone script)

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

'''****************************************************************************
Name: Define Data Boundary of LAS File
Description: This script demonstrates how to delineate data boundaries of 
             LAS files with irregularly clustered points. It is intended for 
             use as a script tool with one input LAS file.
****************************************************************************'''
# Import system modules
import arcpy
import exceptions, sys, traceback

# Set local variables
inLas = arcpy.GetParameterAsText(0) #input LAS file
ptSpacing = arcpy.GetParameterAsText(1) # LAS point spacing
classCode = arcpy.GetParameterAsText(2) # List of integers
returnValue = arcpy.GetParameterAsText(3) # List of strings
outTin = arcpy.GetParameterAsText(4) # TIN created to delineate data area
outBoundary = arcpy.GetParameterAsText(5) # Polygon boundary file

try:
    arcpy.CheckOutExtension("3D")
    # Execute LASToMultipoint
    arcpy.AddMessage("Creating multipoint features from LAS...")
    lasMP = arcpy.CreateUniqueName('lasMultipoint', 'in_memory')
    arcpy.ddd.LASToMultipoint(inLas, LasMP, ptSpacing, class_code, 
                             "ANY_RETURNS", "", sr, inFormat, zfactor)
    # Execute CreateTin
    arcpy.AddMessage("Creating TIN dataset...")
    arcpy.ddd.CreateTin(outTin, sr, "{0} Shape.Z masspoints"\
                       .format(lasMP), "Delaunay")
    # Execute CopyTin
    arcpy.AddMessage("Copying TIN to delineate data boundary...")
    arcpy.ddd.CopyTin(outTin, "{0}_copy".format(outTin))
    # Execute DelineateTinDataArea
    arcpy.AddMessage("Delineating TIN boundary...")
    maxEdge = ptSpacing * 4
    arcpy.ddd.DelineateTinDataArea(outTin, maxEdge, "PERIMETER_ONLY")
    # Execute TinDomain
    arcpy.AddMessage("Exporting data area to polygon boundary...")
    arcpy.ddd.TinDomain(outTin, outBoundary, "POLYGON")
    arcpy.AddMessage("Finished")
    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

Current Workspace

Licensing Information

ArcGIS for Desktop Basic: Requires 3D Analyst

ArcGIS for Desktop Standard: Requires 3D Analyst

ArcGIS for Desktop Advanced: Requires 3D Analyst

11/8/2012

Delineate TIN Data Area (3D Analyst)