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Spline with Barriers

Available with Spatial Analyst license.

Available with 3D Analyst license.


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


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

  • 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.


SplineWithBarriers_3d (Input_point_features, Z_value_field, {Input_barrier_features}, {Output_cell_size}, Output_raster, {Smoothing_Factor})
ParameterExplanationData Type

The input point features containing the z-values to be interpolated into a surface raster.

Feature Layer

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.


The optional input barrier features to constrain the interpolation.

Feature Layer

The cell size at which the output raster will be created.

This will be the value in the environment if it is explicitly set; otherwise, it is the shorter of the width or the height of the extent of the input point features, in the input spatial reference, divided by 250.

Analysis Cell Size

The output interpolated surface raster.

It is always a floating-point raster.

Raster Dataset

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.


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  
env.workspace = "C:/data"
arcpy.SplineWithBarriers_3d("ozone_pts.shp", "ozone", "ozone_barrier.shp",
                             2000, "C:/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:
# Description: Interpolate a series of point features onto a
#    rectangular raster, using optional barriers, using a
#    minimum curvature spline technique.
# Requirements: 3D Analyst Extension.

# Import system modules
import arcpy
from arcpy import env

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

# Set local variables
inPointFeatures = "ca_ozone_pts.shp"
zField = "ozone"
inBarrierFeature = "ca_ozone_barrier.shp"
cellSize = 2000.0
outRaster = "C:/output/splinebout"

# Execute Spline with Barriers
arcpy.SplineWithBarriers_3d(inPntFeat, zField, inBarrierFeature,
                            cellSize, outRaster)

Licensing information

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

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