RFC 14: NoData Bitmasks

Author: Frank Warmerdam
Contact: warmerdam@…
Status: Development

Summary

Some file formats support a concept of a bitmask to identify pixels that are not valid data. This can be particularly valuable with byte image formats where a nodata pixel value can not be used because all pixel values have a valid meaning. This RFC tries to formalize a way of recognising and accessing such nodata bitmasks through the GDAL API.

    virtual CPLErr BitmaskIO( GDALRWFlag, int, int, int, int,
                              GByte *, int, int, GDALDataType,
                              int, int *, int, int, int );

Implementation Plan

This change will be implemented by Frank Warmerdam in trunk in time for the 1.5.0 release.

SWIG Implications

Testing