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

[Even Rouault]

Le mardi 20 mai 2014 12:48:12, Emmanuel Devys a écrit :
> Thanks Peter, Carl, Even, Jukka et al for this interesting discussion on
> adding Georeferencing to image file standards, and capabilities of GMLJP2
> 2.0 (and its GMLCOV capabilities for rectified Grid coverages or
> Georeferenceable Grid coverages), GeoJP2 ...
> 
> I appreciate this idea and action from Even to use the GeoTIFF Box
> mechanism (as documented in the GeoJP2 as explained below) for other
> formats (than JP2K format) such as native JPEG, PNG ... This is outside
> the scope of the Geo-enabled JP2K (and GMLJP2), but of significant
> interest with PNG or JPG data.

A fundamental question that has not been much discussed in this thread is : do 
people really see interest in capturing georeferencing in popular image 
formats like PNG or JPG ? My thinking is that it could be potentially usefull 
in a few situations :
* when a WMS server returns a PNG or JPG.
* when generating tile caches for WMTS / TMS.

> 
> However, if used with JP2 format (specified in ISO 15444-1), this GeoJP2
> (TM) mechanism is an alternative to the GMLJP2 standard. A simple one,
> with no multi-image capability, no annotation (in GML or any other XML
> like, such as SVG) ... but widely supported for providing a Geo-enabled
> capability to JP2 data. The GMLJP2 standard is based on the Gridded
> Coverage model and GML schema in order to provide this capability,
> allowing multi-image, annotations ...
> 
> The new version 2.0 of GMLJP2 (under OGC ballot until June 29) is based on
> GMLCOV schema. Discussions are now initiated between OGC and ISO (TC211 -
> Geographic information) on the " Geo-enabled JP2K" topic and standards.
> Whether GMLJP2 and the GeoTIFF Box in JP2 is to be discussed.

Just curious: what is this "geo-enable JP2K" thing and how is it different from 
JP2 with GMLJP2 or GeoJP2 ? And why would need it to be different... ?

> There are
> other alternatives, one being the auxiliary World files (.j2w) with
> limited information (only 6 parameters, no CRS) ,

Already supported by GDAL, but kind of poor man georeferencing solution... 

> another one being the
> BIIF encapsulation (ISO 12087-5), also called NITF in USA - North America
> and its Geo extension to Geo-reference "raw JP2K codestream" (jc2 format)
> - but the resulting file is no longer a .jp2 file, but a .ntf file.

Not the simplest format to deal with, especially regarding georeferencing, 
since you can have different historical ways of encoding georeferencing in 
NITF. http://gdal.org/frmt_nitf.html mentions at least the IGEOLO, BLOCKA, 
RPC00B, GeoSDE TRE... An advantage is that it brings some way of adding other 
metadata.

Even

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