[gdal-dev] mask bands howto

[Frank Warmerdam]

Vincent Schut wrote:
> Hi,
> 
> is there any up-to-date documentation/tutorial available on the recently 
> added mask bands feature? I found 
> http://trac.osgeo.org/gdal/wiki/rfc15_nodatabitmask, but I was hoping 
> more on something like an api tutorial. The doxygen generated stuff all 
> is empty for mask related functions...

Vincent,

Indeed, the RFC is the majority of the documentation. If you can file
a ticket on specific methods lacking documentation, I'll try and add it.

> Specifically, I'd like to know if it is possible to (using swig python) 
> create a DS (gtiff), and then write boolean data into 
> ds.GetRasterBand(1).GetMaskBand()? Or should I call CreateMaskBand 
> first? This is not entirely clear to me...

Generally you will need to call CreateMaskBand().  The mask you
get back by default will likely be read-only (derived from nodata
values, or the special "all valid" mask).

Best regards,
-- 
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