What is a "Nodata value"
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| − | A nodata value simply is a pixel value in a raster map representing no information. It is ''not to be confused'' with a pixel value of ''0'' (zero). | + | A nodata value simply is a pixel value in a vector or raster map representing no information. It is ''not to be confused'' with a pixel value of ''0'' (zero). |
E.g. in a raster-map containing temperatures of a surface in °C, a pixel value of 0 represents a temperature of 0 °C, while a nodata-pixel simply represents a part of the surface where no information on the temperature is available. | E.g. in a raster-map containing temperatures of a surface in °C, a pixel value of 0 represents a temperature of 0 °C, while a nodata-pixel simply represents a part of the surface where no information on the temperature is available. | ||
Revision as of 11:50, 18 February 2011
QGIS Tutorial
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A nodata value simply is a pixel value in a vector or raster map representing no information. It is not to be confused with a pixel value of 0 (zero).
E.g. in a raster-map containing temperatures of a surface in °C, a pixel value of 0 represents a temperature of 0 °C, while a nodata-pixel simply represents a part of the surface where no information on the temperature is available.
Accumulations of neighboring pixels result in so called “nodata-areas”.
