Summary
Reduces the point density of a feature class of bathymetry soundings or depth points. A shallow or deep-biased output is created by thinning between a defined depth range and thinning according to an approximate distance around points.
Usage
Use this tool to spatially thin sets of points on the basis of depth values.
The output layer will be z-enabled if the input is z-enabled.
If your input is z-enabled and you want to see the elevation values stored with each point feature, use the Add Z Information tool either before or after using Reduce Point Density to add this information to the attribute table.
Depths that fall outside of the range of your Start Depth and End Depth will not be included in the output. If the values don’t include the depth range of the input features, it will result in an empty output.
When setting the Start Depth and End Depth it may help to know the range of your input depths. To see the range, use the Statistics command when right-clicking at the top of your depth field in the attribute table of your input features.
If you want to thin depth values from a raster, use either the Raster To Point tool or the Raster To Multipoint tool.
This tool does not accept a multipoint input. You can use the Multipart To Singlepart tool if the input you want to thin is a multipoint feature class.
Indicate the values of your Start Depth and End Depth according to the Direction you’ve specified. This will affect the output.
To run this tool with a thinning radius that remains constant with depth, only enter a Nominal Start Thinning Radius. To run the tool with a thinning radius that changes gradually with depth, enter both a Nominal Start Thinning Radius and a Nominal End Thinning Radius.
The specified thinning radiuses are approximate in nature. They are intended to honor the Depth Selection Method specified and to guide the spacing between points preserved in the output.
Consider using ModelBuilder to chain together multiple runs of this tool to achieve an output where the thinning radius remains constant for a single depth range, but with multiple densities of points created at different depth ranges.
Syntax
ReducePointDensity_bathymetry (in_features, depth_field, direction, depth_selection_method, nominal_start_thinning_radius, out_features, {start_depth}, {end_depth}, {nominal_end_thinning_radius})| Parameter | Explanation | Data Type |
in_features | The input point features to be thinned. This can be either a single-part point feature class or a shapefile. | Feature Layer |
depth_field | The field in your input features representing your bathymetry depth values. This may either be Shape.Z if your input is z-enabled or any other numeric field type contained in your input. | Field |
direction | Indicates whether your depths are represented by positive or negative values. If your point features contain both negative and positive values, indicate the sign used for the values representing your bathymetry depth points.
| String |
depth_selection_method | Controls whether the output should be shallow biased or deep biased.
| String |
nominal_start_thinning_radius | The approximate thinning radius to be used to reduce the density of points in the output. If no value is entered for the Nominal End Thinning Radius, the thinning radius will use the depth selection method within the radius defined here. In some cases, this means that points that are up to 30 percent closer than the value specified will be preserved in the output. | Linear unit |
out_features | The output feature class that will be created containing the thinned points. | Feature Class |
start_depth (Optional) | The depth value at which the thinning will start. If left blank, this will default to the value of the shallowest point in the input for a shallow-biased result or the value of the deepest point in the input for a deep-biased result. For a shallow-biased result, the Start Depth must be shallower than the End Depth and vice versa for a deep-biased result. | String |
end_depth (Optional) | The depth value at which the thinning will end. If left blank, this will default to the value of the deepest point in the input for a shallow-biased result or the value of the deepest point in the input for a deep-biased result. For a shallow-biased result, the End Depth must be deeper than the Start Depth and vice versa for a deep-biased result. | String |
nominal_end_thinning_radius (Optional) | The approximate and secondary thinning radius to be used to reduce the density of the points in the output. This will create a thinning radius that changes gradually with depth. The start thinning radius will be applied at the start depth value and the end thinning radius will be applied at the end depth value. A thinning radius will then be calculated for depths that fall between the indicated start and end depth range. For example, with start and end depths of 50 and 100, and with start and end thinning radiuses of 500 and 1,000, a point with a depth of 75 would have a thinning radius of 750 applied to it. The units selected must be the same as those selected from the Start Thinning Radius parameter. | Linear unit |
Code Sample
ReducePointDensity example (stand-alone script)
The following stand-alone script demonstrates how to use the ReducePointDensity tool.
# name: ReducePointDensity_Example.py
# description: Reduces the point density of an input set of points.
# requirements: ArcGIS for Maritime Bathymetry
# for a stand-alone script, check out the extension first
arcpy.CheckOutExtension("Bathymetry")
# set up parameters
inFeatures = "C:/data/BIS_Features.gdb/Depths"
depthField = "Depth"
direction = "POSITIVE_UP"
depthSelectionMethod = "SHALLOW_BIASED"
startThinningRadius = 500
thinningUnits = "Meters"
outFeatures = "C:/data/BIS_Features/ThinnedDepths"
startDepth = 50
endDepth = 100
endThinningRadius = 1000
# execute the tool
arcpy.ReducePointDensity_bathymetry(inFeatures, depthField, direction, depthSelectionMethod, startThinningRadius, thinningUnits, outFeatures, startDepth, endThinningRadius)
Environments
Licensing Information
- ArcGIS for Desktop Basic: No
- ArcGIS for Desktop Standard: Requires Maritime Bathymetry
- ArcGIS for Desktop Advanced: Requires Maritime Bathymetry