[OSGeo-Standards] [gdal-dev] Idea: GeoTIFF box in JPEG to add georeferencing

[Peter Baumann]

PS: not sure all on this list are aware of this overview page:
http://external.opengeospatial.org/twiki_public/CoveragesDWG/CoveragesBigPicture

-Peter


On 05/12/2014 11:38 PM, Peter Baumann wrote:
> Hi all,
>
> just saw this, thought I'd chime in being the editor of GMLCOV :)
> Any questions, I'll gladly try to answer, I'm just on the road currently, so 
> expect a delay of a day or so.
>
> Trying to respond to what has been raised below:
>
> On 05/12/2014 11:18 PM, Even Rouault wrote:
>> Le lundi 12 mai 2014 23:05:21, Jukka Rahkonen a écrit :
>>> Even Rouault <even.rouault <at> mines-paris.org> writes:
>>>
>>> ...
>>>
>>>>> In light of this, it may be better to use an xml or textual
>>>>> representation and embed it inside an XMP block, which is supported
>>>>> for many formats[1]. Also it would allow for easier human-reading.
>>>> Yes, that's one possibility. Which comes back to GMLJP2 unless there are
>>> other
>>>
>>>> standards...
>>>>
>>>> I'd want to build on something that is a "real" standard or a de-facto
>>>> standard, but not reinvent everything from scratch.
>>> What GMLJP2 gives as a bonus is the axis order trouble
>
> actually, no. GMLJP2 relies on GMLCOV which defines axis order. Each coverage 
> has a Native CRS which is defined via an OGC URI (which, in the case of EPSG, 
> refers to the OGP maintained database). In the CRS definition the axis is 
> given unambiguously.
>
> If you don't want to go to that database, use the axisLabels attribute in the 
> Envelope, it lists axes in their proper sequence.
>
>
>>> and not totally
>>> clear interpretation if origin is in the centre (probably it is) or in the
>>> corner of a pixel,
>
> naively, GMLCOV follows the pixel-in center interpretation. However, encodings 
> may override this, such as GeoTIFF (see the pertaining adopted spec [1]).
>
> [1] https://portal.opengeospatial.org/files/?artifact_id=50118
>
>
>>> and rectified grid does not support ground control
>>> points.
>
> yes, because it is rectified. If you want more degree of freedom do not use 
> RectifiedGridCoverage but ReferenceableGridCoverage. In conjunction with GML 
> 3.3 ( a compatible enhancement of GML 3.2.1) this gives you irregular and 
> warped grids. We're not completely done, though, and would be glad about your 
> support in some advanced issues. Note that this work is all voluntary and 
> relies on some project financing to be done. Up to now, EC and ESA have been 
> generous, and so we are going ahead step by step.
>
>
>>> Thus GMLJP2 is at least not better in everything, it has also
>>> drawbacks.
>> Hi Jukka,
>>
>> Yes, for all your above reasons, I would prefer to avoid it.
>
> so which ones are remaining, following the clarification you mention below?
>
> cheers,
> Peter
>
>> Although the axis order trouble (the one of EPSG) and interpretation of origin
>> (pixel center) should be mostly clarified with the revised version.
>> As far as ground countrol points are concerned, I've not really looked at the
>> capabilities of GMLCov, so perhaps there's something in it for that.
>> Otherwise, that would be indeed a drawback.
>>
>>> -Jukka Rahkonen-
>>>
>>> _______________________________________________
>>> gdal-dev mailing list
>>> gdal-dev at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>

-- 
Dr. Peter Baumann
  - Professor of Computer Science, Jacobs University Bremen
    www.faculty.jacobs-university.de/pbaumann
    mail: p.baumann at jacobs-university.de
    tel: +49-421-200-3178, fax: +49-421-200-493178
  - Executive Director, rasdaman GmbH Bremen (HRB 26793)
    www.rasdaman.com, mail: baumann at rasdaman.com
    tel: 0800-rasdaman, fax: 0800-rasdafax, mobile: +49-173-5837882
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