[Gdal-dev] Adding Fugawi .JPR Support to GDAL

Frank Warmerdam warmerdam at pobox.com
Wed Aug 25 18:08:09 EDT 2004


Christian Doenges wrote:
> I don't know all the ESRI extensions to TFW, so I don't know if any 
> conflict with the Fugawi extensions. Is there a specification?
> 
> If I can rule out conflicts, I will simply loop through the lines and 
> match what I can. When I'm done, I will collect the data and cluster it 
> into metadata, as outlined above.
> 
> If I can't rule out conflicts, I will insist on .jpr.

Christian,

I am not aware of a specification.  I would suggest sticking to .jpr for now
if that is not big imposition.

On the issue of changes to each of the drivers, I think some of that is
inevitable.  For instance, some of the drivers that have never had support
for a projection before will just fall through to the default GDALDataset
GetProjectionRef() which just returns an empty string.  The default
SetProjection() would also just issue an error message and return.

Some other kinds of data, such as metadata is built into the base class and
can be set on any GDALDataset even if it hasn't made any special effort to
implement metadata methods.

While the original design decisions on my part can be questioned, the net
effect is now that you will need to look over each of the drivers you would
like to support JPR files and potentially override some of the requested
methods, and add new data items to the derived dataset class.  This has already
been done for format drivers support geotransforms from world files for instance.

Now, this task shouldn't really be too onerous but it should be kept in mind.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent




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