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 -- Geospatial professional services http://even.rouault.free.fr/services.html _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
