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Raster To Multipoint

Summary

Converts raster cell centers into 3D multipoint features whose Z values reflect the raster cell value.

Usage

  • Consider using this tool if you have raster elevation data and require access to the functional capabilities provided by a triangulated surface, as multipoint features can be loaded into a TIN or Terrain dataset.

  • When the input raster is very large in size, consider applying a thinning method to reduce the number of cells that get exported to the multipoint feature class.

    • Use the Z Tolerance thinning method when it is important to preserve vertical accuracy.
    • Use the Kernel thinning method when it is important to control the horizontal sample distance.
    • Use the VIP thinning method if the resulting multipoints will be primarily applied for visualization applications. This method is relatively fast, outputs a predictable number of points, and is good at selecting local peaks and pits. However, it is sensitive to noise and may ignore topographic features that span an extent that is larger than the 3 cell by 3 cell area.
    • Use the VIP Histogram option as an initial step to apply the VIP thinning method, as it produces a histogram of the significance scores that lets you know the number of points that would be selected with each incrementing percentile value.

Syntax

RasterToMultipoint_3d (in_raster, out_feature_class, {out_vip_table}, {method}, {kernel_method}, {z_factor})
ParameterExplanationData Type
in_raster

The raster to process.

Raster Layer
out_feature_class

The feature class that will be produced by this tool.

Feature Class
out_vip_table
(Optional)

The histogram table to be produced when VIP Histogram is specified for the Method parameter.

Table
method
(Optional)

The thinning method applied to the input raster to select a subset of cells that will be exported to the multipoint feature class.

  • NO_THIN —No thinning will be applied. This is the default.
  • ZTOLERANCE <value> —Only exports the cells that are required for maintaining a surface within the specified Z-range of the input raster. The corresponding value reflects the maximum allowable difference in z units between the input raster and the surface created from the output multipoint feature class. When selecting this method, the thinning value defaults to one tenth of the z range of the input raster.
  • KERNEL <value> —Divides the raster into equal sized tiles based on the thinning value, then selects one or two cells which meet the criteria defined by the designated kernel method. The corresponding value defaults to 3, which means the raster would be divided into 3 cell by 3 cell windows.
  • VIP <value> —Employs a roving 3 cell by 3 cell window that is used to create a 3-dimensional best fit plane. Each cell is given a significance score based on its absolute deviation from this plane. A histogram of these scores is then used to determine the cells that get exported. The corresponding value reflects the percentile rank along the histogram of significance scores. This value defaults to 5.0, which means the cells whose score was within the top 5% of the histogram will be exported.
  • VIP_HISTOGRAM —Creates a table to view the actual significance values and the corresponding number of points associated with those values.
String
kernel_method
(Optional)

The selection method used within each kernel neighborhood when kernel thinning is applied on the input raster.

  • MIN —A point is created at the cell with the smallest elevation value found in the kernel neighborhood. This is the default.
  • MAX —A point is created at the cell with the largest elevation value found in the kernel neighborhood.
  • MINMAX —Two points are created at the cells with the smallest and largest Z values found in the kernel neighborhood.
  • MEAN —A point is created at the cell whose elevation value is closest to the average of the cells in the kernel neighborhood.
String
z_factor
(Optional)

The factor by which Z values will be multiplied. This is typically used to convert Z linear units to match XY linear units. The default is 1, which leaves elevation values unchanged.

Double

Code Sample

RasterToMultipoint 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.RasterToMultipoint_3d("elevation.tif", "","elev_VIP.dbf", "VIP_HISTOGRAM", "", "1")
RasterToMultipoint example 2 (stand-alone script)

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

'''*********************************************************************
Name: RasterToMultipoint Example
Description: This script demonstrates how to use
             the RasterToMultipoint tool to create multipoint datasets
             fot all IMG rasters in a target workspace.
**********************************************************************'''
# Import system modules
import arcpy
from arcpy import env
import exceptions

try:
    arcpy.CheckOutExtension("3D")
    # Set default workspace
    env.workspace = "C:/data"
    # Create the list of IMG rasters
    rasterList = arcpy.ListRasters("*", "IMG")
    # Loop the process for each raster
    if rasterList:
        for raster in rasterList:
            # Set Local Variables
            # [:-4] strips the last 4 characters (.img) from the raster name
            outTbl = "VIP_" + raster[:-4] + ".dbf"
            method = "VIP_HISTOGRAM"
            zfactor = 1
            #Execute RasterToMultipoint
            arcpy.ddd.RasterToMultipoint(raster, "",outTbl, method, "", zfactor)
    else:
        "There are no IMG rasters in the " + env.workspace + " directory."
except Exception as e:
    # Returns any other error messages
    print e.message

Environments

Licensing Information

  • ArcGIS for Desktop Basic: Requires 3D Analyst
  • ArcGIS for Desktop Standard: Requires 3D Analyst
  • ArcGIS for Desktop Advanced: Requires 3D Analyst

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