com.esri.arcgis.geoprocessing.tools.spatialanalysttools
Class Idw

java.lang.Object
  com.esri.arcgis.geoprocessing.AbstractGPTool
      com.esri.arcgis.geoprocessing.tools.spatialanalysttools.Idw

All Implemented Interfaces:

GPTool

public class Idw
extends AbstractGPTool

Interpolates a raster surface from points using an inverse distance weighted (IDW) technique. The IDW tool is contained in the Spatial Analyst Tools tool box.

Usage tips:

• The output value for a cell using Inverse Distance Weighting (IDW) is limited to the range of the values used to interpolate. Because IDW is a weighted distance average, the average cannot be greater than the highest or less than the lowest input. Therefore, it cannot create ridges or valleys if these extremes have not already been sampled (Watson and Philip, 1985).
• The best results from IDW are obtained when sampling is sufficiently dense with regard to the local variation you are attempting to simulate. If the sampling of input points is sparse or uneven, the results may not sufficiently represent the desired surface (Watson and Philip, 1985).
• The influence of an input point on an interpolated value is isotropic. Since the influence of an input point on an interpolated value is distance related, IDW is not "ridge preserving" (Philip and Watson, 1982).
• 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 affect 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 tool in the Spatial Statistics toolbox is useful for identifying any coincident points in your data.
• The barriers option is used to specify the location of linear features known to interrupt the surface continuity. These features do not have z-values. Cliffs, faults, and embankments are typical examples of barriers. Barriers limit the selected set of the input sample points used to interpolate output z-values to those samples on the same side of the barrier as the current processing cell. Separation by a barrier is determined by line-of-sight analysis between each pair of points. This means that topological separation is not required for two points to be excluded from each other's region of influence. Input sample points that lie exactly on the barrier line will be included in the selected sample set for both sides of the barrier.
• Barrier features are input as polyline features. IDW only uses the x,y coordinates for the linear feature; therefore, it is not necessary to provide z-values for the left and right sides of the barrier. Any z-values provided will be ignored.
• Using barriers will significantly extend the processing time.
• This tool has a limit of approximately 45 million input points. If your input feature class contains more than 45 million points, the tool may fail to create a result. You can avoid this limit by interpolating your study area in several pieces, making sure there is some overlap in the edges, and then mosaicking the results to create a single large raster dataset. Alternatively, you can use a to store and visualize points and surfaces comprised of billions of measurement points.If you have the Geostatistical Analyst extension, you may be able to process larger datasets.
• The input feature data must contain at least one valid field.

Field Summary

Fields inherited from class com.esri.arcgis.geoprocessing.AbstractGPTool

vals

Constructor Summary

Idw()
Creates the IDW tool with defaults.

Idw(Object inPointFeatures, Object zField, Object outRaster)
Creates the IDW tool with the required parameters.

Method Summary

Object	getCellSize() Returns the Output cell size parameter of this tool .
Object	getInBarrierPolylineFeatures() Returns the Input barrier polyline features parameter of this tool .
Object	getInPointFeatures() Returns the Input point features parameter of this tool .
Object	getOutRaster() Returns the Output raster parameter of this tool .
double	getPower() Returns the Power parameter of this tool .
Object	getSearchRadius() Returns the Search radius parameter of this tool .
String	getToolboxAlias() Returns the alias of the tool box containing this tool.
String	getToolboxName() Returns the name of the tool box containing this tool.
String	getToolName() Returns the name of this tool.
Object	getZField() Returns the Z value field parameter of this tool .
void	setCellSize(Object cellSize) Sets the Output cell size parameter of this tool .
void	setInBarrierPolylineFeatures(Object inBarrierPolylineFeatures) Sets the Input barrier polyline features parameter of this tool .
void	setInPointFeatures(Object inPointFeatures) Sets the Input point features parameter of this tool .
void	setOutRaster(Object outRaster) Sets the Output raster parameter of this tool .
void	setPower(double power) Sets the Power parameter of this tool .
void	setSearchRadius(Object searchRadius) Sets the Search radius parameter of this tool .
void	setZField(Object zField) Sets the Z value field parameter of this tool .

Methods inherited from class com.esri.arcgis.geoprocessing.AbstractGPTool

getParameterValues, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Idw

public Idw()

Creates the IDW tool with defaults.

Initializes the array of tool parameters with the default values specified when the tool was created.

Idw

public Idw(Object inPointFeatures,
           Object zField,
           Object outRaster)

Creates the IDW tool with the required parameters.

Initializes the array of tool parameters with the values as specified for the required parameters and with the default values for the other parameters.

Parameters:

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

zField - 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 contains z-values.

outRaster - the output interpolated surface raster.

Method Detail

getInPointFeatures

public Object getInPointFeatures()

Returns the Input point features parameter of this tool . This parameter is the input point features containing the z-values to be interpolated into a surface raster. This is a required parameter.

Returns:

the Input point features

setInPointFeatures

public void setInPointFeatures(Object inPointFeatures)

Sets the Input point features parameter of this tool . This parameter is the input point features containing the z-values to be interpolated into a surface raster. This is a required parameter.

Parameters:

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

getZField

public Object getZField()

Returns the Z value field parameter of this tool . This parameter is 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 contains z-values. This is a required parameter.

Returns:

the Z value field

setZField

public void setZField(Object zField)

Sets the Z value field parameter of this tool . This parameter is 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 contains z-values. This is a required parameter.

Parameters:

zField - 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 contains z-values.

getOutRaster

public Object getOutRaster()

Returns the Output raster parameter of this tool . This parameter is the output interpolated surface raster. This is a required parameter.

Returns:

the Output raster

setOutRaster

public void setOutRaster(Object outRaster)

Sets the Output raster parameter of this tool . This parameter is the output interpolated surface raster. This is a required parameter.

Parameters:

outRaster - the output interpolated surface raster.

getCellSize

public Object getCellSize()

Returns the Output cell size parameter of this tool . This parameter is 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. This is an optional parameter.

Returns:

the Output cell size

setCellSize

public void setCellSize(Object cellSize)

Sets the Output cell size parameter of this tool . This parameter is 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. This is an optional parameter.

Parameters:

cellSize - 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.

getPower

public double getPower()

Returns the Power parameter of this tool . This parameter is the exponent of distance. controls the significance of surrounding points on the interpolated value. A higher power results in less influence from distant points. it can be any real number greater than 0, but the most reasonable results will be obtained using values from 0.5 to 3. The default is 2. This is an optional parameter.

Returns:

the Power

setPower

public void setPower(double power)

Sets the Power parameter of this tool . This parameter is the exponent of distance. controls the significance of surrounding points on the interpolated value. A higher power results in less influence from distant points. it can be any real number greater than 0, but the most reasonable results will be obtained using values from 0.5 to 3. The default is 2. This is an optional parameter.

Parameters:

power - the exponent of distance. controls the significance of surrounding points on the interpolated value. A higher power results in less influence from distant points. it can be any real number greater than 0, but the most reasonable results will be obtained using values from 0.5 to 3. The default is 2.

getSearchRadius

public Object getSearchRadius()

Returns the Search radius parameter of this tool . This parameter is the Radius class defines which of the input points will be used to interpolate the value for each cell in the output raster. there are two types of radius: RadiusVariable and RadiusFixed. A Variable search radius is used in order to find a specified number of input sample points for the interpolation. The Fixed type uses a specified fixed distance within which all input points will be used for the interpolation. The Variable type is the default. This is an optional parameter.

Returns:

the Search radius

setSearchRadius

public void setSearchRadius(Object searchRadius)

Sets the Search radius parameter of this tool . This parameter is the Radius class defines which of the input points will be used to interpolate the value for each cell in the output raster. there are two types of radius: RadiusVariable and RadiusFixed. A Variable search radius is used in order to find a specified number of input sample points for the interpolation. The Fixed type uses a specified fixed distance within which all input points will be used for the interpolation. The Variable type is the default. This is an optional parameter.

Parameters:

searchRadius - the Radius class defines which of the input points will be used to interpolate the value for each cell in the output raster. there are two types of radius: RadiusVariable and RadiusFixed. A Variable search radius is used in order to find a specified number of input sample points for the interpolation. The Fixed type uses a specified fixed distance within which all input points will be used for the interpolation. The Variable type is the default.

getInBarrierPolylineFeatures

public Object getInBarrierPolylineFeatures()

Returns the Input barrier polyline features parameter of this tool . This parameter is polyline features to be used as a break or limit in searching for the input sample points. This is an optional parameter.

Returns:

the Input barrier polyline features

setInBarrierPolylineFeatures

public void setInBarrierPolylineFeatures(Object inBarrierPolylineFeatures)

Sets the Input barrier polyline features parameter of this tool . This parameter is polyline features to be used as a break or limit in searching for the input sample points. This is an optional parameter.

Parameters:

inBarrierPolylineFeatures - polyline features to be used as a break or limit in searching for the input sample points.

getToolName

public String getToolName()

Returns the name of this tool.

Returns:

the tool name

getToolboxName

public String getToolboxName()

Returns the name of the tool box containing this tool.

Returns:

the tool box name

getToolboxAlias

public String getToolboxAlias()

Returns the alias of the tool box containing this tool.

Returns:

the tool box alias