ArcMap

Spline with Barriers

Available with Spatial Analyst license.

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

  • This tool requires the Java runtime environment Version 6, or higher, to be installed. The Java Runtime Environment can be downloaded for free from http://www.java.com/en/download.

  • The resulting smooth surface from is constrained by the input barrier features.

  • 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.

  • If a cell size of 0 is entered, the cell size actually used will be the shorter of the width or the height of the extent of the input point features, in the input spatial reference, divided by 250.

  • The barrier features are rasterized and the cell center is used to decide whether the cell falls within a polygon or whether the cell becomes a barrier for polyline features.

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

Syntax

SplineWithBarriers (Input_point_features, Z_value_field, {Input_barrier_features}, {Output_cell_size}, {Smoothing_Factor})
ParameterExplanationData 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 at which the output raster will be created.

If a value of 0 is entered, the shorter of the width or the height of the extent of the input point features in the input spatial reference, divided by 250, will be used as the cell size.

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

NameExplanationData 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 and Java Runtime 
#    Environment Version 5.0, or higher.

# 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

# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")

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

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

Environments

Licensing information

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

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