Natural Neighbor (Spatial Analyst)

Available with Spatial Analyst license.

Available with 3D Analyst license.

Summary

Interpolates a raster surface from points using a natural neighbor technique.

Learn more about how Natural Neighbor works

Usage

• If the cell center of the perimeter cells of the output raster fall outside the convex hull (defined by the input points), then those cells will be assigned NoData values. If an input point falls within one of these perimeter cells and the cell center falls outside the convex hull, the cell will still be assigned a value of NoData.

• The Output cell size can be defined by a numeric value or obtained from an existing raster dataset. If the cell size hasn’t been explicitly specified as the parameter value, it is derived from the Cell Size environment if it has been specified. If the parameter cell size or the environment cell size have not been specified, but the Snap Raster environment has been set, the cell size of the snap raster is used. If nothing is specified, the cell size is calculated from the shorter of the width or height of the extent divided by 250, in which the extent is in the Output Coordinate System specified in the environment.

• If the cell size is specified using a numeric value, the tool will use it directly for the output raster.

  If the cell size is specified using a raster dataset, the parameter will show the path of the raster dataset instead of the cell size value. The cell size of that raster dataset will be used directly in the analysis, provided the spatial reference of the dataset is the same as the output spatial reference. If the spatial reference of the dataset is different than the output spatial reference, it will be projected based on the selected Cell Size Projection Method.

• Some input datasets may have several points with the same x,y coordinates. If the values of the points at the common location are the same, they are considered duplicates and have no effect on the output. If the values are different, they are considered coincident points.

  The various interpolation tools may handle this data condition differently. For example, in some cases, the first coincident point encountered is used for the calculation; in other cases, the last point encountered is used. This may cause some locations in the output raster to have different values than what you might expect. The solution is to prepare your data by removing these coincident points. The Collect Events tool in the Spatial Statistics toolbox is useful for identifying any coincident points in your data.

• For data formats that support Null values, such as file geodatabase feature classes, a Null value will be ignored when used as input.

• This tool has a limit of approximately 15 million input points. If your input feature class contains more than a very large number of points (around 15 million or greater), the tool may fail to create a result.

  You can avoid this limit by processing your study area in several sections and mosaicking the results into a single large raster dataset. Ensure that there is some overlap between the sections. Alternatively, you can use a Terrain dataset to store and visualize points and surfaces comprised of billions of measurement points.

• It is recommended that the input data be in a projected coordinate system rather than in a geographic coordinate system.

• If the ArcGIS 3D Analyst extension is available, an alternative approach is to use a TIN dataset. First, create a TIN surface from your source data. Then, convert the resulting TIN to a raster with the TIN To Raster tool, using the Natural Neighbors option. This is particularly useful if you have breaklines or an irregularly shaped data area.

• See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.

Parameters

Dialog

Label	Explanation	Data Type
Input point features	The input point features containing the z-values to be interpolated into a surface raster.	Feature Layer
Z value field	The field that holds a height or magnitude value for each point. This can be a numeric field or the Shape field if the input point features contain z-values.	Field
Output cell size (Optional)	The cell size of the output raster that will be created. This parameter can be defined by a numeric value or obtained from an existing raster dataset. If the cell size hasn't been explicitly specified as the parameter value, the environment cell size value will be used if specified; otherwise, additional rules will be used to calculate it from the other inputs. See the usage section for more detail.	Analysis Cell Size

Return Value

Label	Explanation	Data Type
Output raster	The output interpolated surface raster. It is always a floating-point raster.	Raster

Python

NaturalNeighbor(in_point_features, z_field, {cell_size})

Name	Explanation	Data Type
in_point_features	The input point features containing the z-values to be interpolated into a surface raster.	Feature Layer
z_field	The field that holds a height or magnitude value for each point. This can be a numeric field or the Shape field if the input point features contain z-values.	Field
cell_size (Optional)	The cell size of the output raster that will be created. This parameter can be defined by a numeric value or obtained from an existing raster dataset. If the cell size hasn't been explicitly specified as the parameter value, the environment cell size value will be used if specified; otherwise, additional rules will be used to calculate it from the other inputs. See the usage section for more detail.	Analysis Cell Size

Return Value

Name	Explanation	Data Type
out_raster	The output interpolated surface raster. It is always a floating-point raster.	Raster

Code sample

NaturalNeighbor example 1 (Python window)

This example inputs a point shapefile and interpolates the output surface as a TIFF raster.

import arcpy
from arcpy import env  
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outNaturalNeighbor = NaturalNeighbor("ozone_pts.shp", "ozone", 2000)
outNaturalNeighbor.save("C:/sapyexamples/output/nnout.tif")

NaturalNeighbor example 2 (stand-alone script)

This example inputs a point shapefile and interpolates the output surface as a Grid raster.

# Name: NaturalNeighbor_Ex_02.py
# Description: Interpolate a series of point features onto a 
#    rectangular raster using Natural Neighbor interpolation.
# Requirements: Spatial Analyst Extension

# Import system modules
import arcpy
from arcpy import env
from arcpy.sa import *

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

# Set local variables
inPointFeatures = "ca_ozone_pts.shp"
zField = "ozone"
cellSize = 40000

# Execute NaturalNeighbor
outNatNbr = NaturalNeighbor(inPointFeatures, zField, cellSize)

# Save the output 
outNatNbr.save("C:/sapyexamples/output/nnout02")

Environments

Auto Commit, Cell Size, Cell Size Projection Method, Current Workspace, Extent, Geographic Transformations, Output CONFIG Keyword, Output Coordinate System, Scratch Workspace, Snap Raster, Tile Size

Licensing information

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