[postgis-users] Proposed SQL interface for PGRaster

[Mark Cave-Ayland]

On Tue, 2006-12-05 at 16:36 -0500, Stephen Marshall wrote:
> Mark,
> 
> I agree that the user needs to know about the endian-ness of the data.  
> However, I'm envisioning a system where the data is returned in a 
> well-known image format, e.g. Geo-TIFF, JPEG2000, etc.  Thus I'm 
> delegating the requirement to the storage format.  These formats should 
> contain either conventions about endian-ness, or a parameter that 
> describe which endian-ness was used. 
> 
> I think your concern could be addressed by adding an additional 
> requirement for an acceptable raster format:
> * Byte order of the data values, e.g. big endian or little endian
> 
> Do you agree?
> Steve


Hi Steve,

Yes, that seems like a reasonable assumption. I must admit, it wasn't
clear to me from reading the specification whether the plan was to
simply place the complete raster file (e.g. TIFF or JPEG) in the
database or just to store an array of uncompressed data values. If the
raw file formats themselves are stored, then as you mention this
shouldn't be an issue.

This does make the case of creating on-the-fly rasters interesting;
should they be stored in a lossy/lossless format? Is this what the
data_type parameter for pgr_create_raster() is for, e.g. to specify TIFF
or JPEG?


Kind regards,

Mark.