NoData value

The NoData value is a special numeric value that is used to flag grid cells that do not have valid data values. Most Whitebox GAT tools handle NoData values differently and these grid cells are displayed specially, usually transparently. The NoData value can be any numeric value within the range of values that can be represented for a given data type (i.e. double-precision floating point, single-precision floating point, integer, or byte). The NoData value is set within the header file (.dep) of a Whitebox raster. NoData is most commonly set to -32,768, the smallest value that a 16-bit signed short integer can hold, by raster tools. This value is a good candidate for NoData because it is unlikely to be needed as a valid data value. Notice that it is not possible to use -32,768 for grids of a Byte data type, which is why this data type is being phased out.

Background areas can be assigned the NoData value by using either the SetNoData tool or the Reclass tool. Areas of NoData values in an image can be identified using the IsNoData tool.

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