[postgis-users] A PostGIS-Raster data proposal

[Stephen Woodbridge]

Frank Warmerdam wrote:

[snip]

>> Using a more flexible set of image format does give me some concern
>> regarding image geonavigation.  One thing that drew me towards using a
>> single image format for storage was to have less variation in how
>> metadata (like image navigation) would be provided.  Assuming a more
>> flexible GDAL implementation, how would such metadata be extracted from
>> the image?  Does GDAL provide a generic way to extract image navigation
>> information from any format, e.g. the location of the image's bounding
>> box in earth-oriented coordinates? 
> 
> GDAL does support a generic model for geolocation information and
> supports extracting it from the target file or associated files such as
> world files.  In the context of rasters in postgis, I would expect most
> metadata and geolocation information (at least a bounding polygon) would
> actually be kept distinct from the BLOB containing the raster.
> 
> For multi file formats we would either just not support them in PostGIS,
> or have some way of treating several files as a "package" in a blob.  I'd
> be inclined to ignore multi-file formats for the time being.

I think this could be handled with the data loader. It would take the 
multi-file representation and read the components and load the data 
appropriately.  I would think that these would be considered as 
attributes associated to the image blob.

-Steve