[gdal-dev] Writing a GDAL Driver: two questions

[Martin Lambers]

Hello all,

I am writing a GDAL Driver for the GTA format
<http://www.nongnu.org/gta/>. The driver can already read GTA files and
create files with CreateCopy().

- What actions must a Driver support in GA_Update mode? Is it ok if it
just implements GDALPamRasterBand::IWriteBlock() for data updates? Or
does it have to support metadata updates, too?

- A GTA file can have bands with different data types mixed freely (e.g.
Byte, UInt16, CFloat32 all in one file). The Open() function can create
a matching GDALDataset without problems, and the gdal* programs seem to
be able to handle this. But the GDALDriver::Create() function only
allows to create data sets with the same data type for all bands. Are
different data types supported, or should I restrict the driver to only
open files that use the same data type for all bands?

Best regards,
Martin