Spline with Barriers (Spatial Analyst)

Summary

Interpolates a raster surface, using barriers, from points using a minimum curvature spline technique. The barriers are entered as either polygon or polyline features.

Learn more about how Spline with Barriers works

Usage

• The output raster cannot have more than 65,536 columns or rows.

• The Output cell size 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, 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 specified Cell Size Projection Method value.

• 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 the Spline with Barriers tool, by default the values for each set of coincident points will be averaged.

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

• 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
Input barrier features (Optional)	The optional input barrier features to constrain the interpolation.	Feature Layer
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
Smoothing Factor (Optional)	The parameter that influences the smoothing of the output surface. No smoothing is applied when the value is zero and the maximum amount of smoothing is applied when the factor equals 1. The default is 0.0.	Double

Return Value

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

Python

SplineWithBarriers(Input_point_features, Z_value_field, {Input_barrier_features}, {Output_cell_size}, {Smoothing_Factor})

Name	Explanation	Data Type
Input_point_features in_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
Input_barrier_features (Optional)	The optional input barrier features to constrain the interpolation.	Feature Layer
Output_cell_size 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
Smoothing_Factor (Optional)	The parameter that influences the smoothing of the output surface. No smoothing is applied when the value is zero and the maximum amount of smoothing is applied when the factor equals 1. The default is 0.0.	Double

Return Value

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

Code sample

SplineWithBarriers 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"
outSplineBarriers = SplineWithBarriers("ca_ozone_pts.shp", "ozone", 
                                       "ca_ozone_barrier.shp", 2000)
outSplineBarriers.save("C:/sapyexamples/output/splinebarrierout.tif")

SplineWithBarriers example 2 (stand-alone script)

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

# Name: SplineWithBarriers_Ex_02.py
# Description: Interpolate a series of point features onto a
#    rectangular raster, using optional barriers, using a
#    minimum curvature spline technique.
# 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"
inBarrierFeature = "ca_ozone_barrier.shp"
cellSize = 2000.0

# Execute Spline with Barriers
outSplineBarriers = SplineWithBarriers(inPointFeatures,
                          zField, inBarrierFeature, cellSize)

# Save the output
outSplineBarriers.save("C:/sapyexamples/output/splinebout02")

Environments

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