The Nearest Neighbor method is used with regularly spaced data points. This method is an exact interpolator and does not extrapolate beyond the z range of the data.
Nearest Neighbor Method Options
- Parameter Unit
Specifies whether spatial parameters are defined in cell units or distance units. The units should be supported by MapInfo Pro, for example, the options for Distance unit include: US Survey feet, yards, rods, chains, miles, nautical miles, millimeters, centimeters, meters, inches, links and kilometers. If you choose Distance, you need to select a distance unit from the Distance Unit drop-down list.
- Search Radius
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The maximum distance allowed between a grid cell and the neighboring input data points that will be considered when computing its value. The distance value determines whether these points are considered in the distance weighing average. The Search Radius must be greater than 0, and specified in Parameter Units type.
Click More Options to open the following advanced options.
Smoothing Method
You can apply smoothing on the gridded data to produce smoother surface. Smoothing is used to enhance the sharpness of an image or improve the appearance of the edges. Select a suitable Smoothing method and level for your data.
Smoothing Level - Move the smoothing slider to set the smoothing level for the output raster. You can set a value between 0 to 6. A value of zero applies no smoothing. A value of 6 applies maximum smoothing.
- Clipping
- The Clipping control provides options to limit the extents of the interpolated raster, so it more closely approximates the distribution of the input data. Enabling this option can improve the appearance of the output raster when interpolating irregularly spaced input data, where the interpolation methods (such as Triangulation, Minimum Curvature or Natural Neighbor) has interpolated across large gaps in the input data.
- None - No clipping is applied to the raster cells.
- Near Only - The Near value represents the maximum distance from a source input data point for which an interpolated raster cell will be created. Cells in the raster which lie at a distance greater than the Near distance will be assigned a null value. This method has the same effect as applying a distance buffer to the source data points equal to the near distance.
- Near/Far - Interpolated cells in the output raster will be clipped to the near distance if no other data point is found within the Far distance that meet the angular search constraints. Applying both Near and Far clipping can be useful to constrain the interpolated raster to a required distance from the source points, while also permitting larger gaps to be interpolated in irregularly spaced data.
- Polygon - You can provide a TAB file of polygon(s) to clip the output raster to the polygon boundaries. You can specify whether to clip a region outside or inside the raster bounds. However, it does not support polygons with holes.
Coincident Points Method
The Coincident Points drop-down list controls the handling of multiple data points at the same location. For more information see, Coincident Point Methods.
Raster Geometry
Cell Size
Specify the cell size for the output raster in the Cell Size box. The cell size defines the width and height of a raster cell in distance units. If the raster cells are square both width and height are specified with same value.
By default, Automatic is selected which means will calculate the output raster cell size based on source data points. Click Suggest, to see the calculated cell size value in the box before it is processed. You can modify the cell size value to produce output raster with the desired cell size. The Suggest button is active only when the input data source is in MapInfo native format.
Output Geometry
The Output Geometry allows you to limit the output data points according to specified region (bounds) and ignore all points that lie outside of the specified region. The data within the specified bounds will be written in the output file. To specify the Raster Bounds, enter coordinate values for raster origin and extent.
- Min X - X coordinate of the origin (lower left corner of the cell).
- Min Y - Y coordinate of the origin (lower left corner of the cell).
- Max X - The maximum coordinate value for X (upper right corner of the cell).
- Max Y - The maximum coordinate value for Y (upper right corner of the cell).
The output file will contain data for the specified region only.
If required, click More Options to specify the projection for the output raster. If the input file is a MapInfo .TAB file, projection values are read from the input file, which you can override here.
- Category - The Category drop-down list consists of all projection systems supported by MapInfo Pro. For example, Longitude/Latitude, Universal Transverse Mercator (ED 50), Universal Transverse Mercator (NAD 27 for Canada), etc.
- Sub Category - The Sub Category drop-down list consists of the type of projection based on the selected projection system.