On 28 April 2011 05:37, Andrea Aime <[email protected]> wrote: > Hi, > some months ago I started a discussion on GeoServer devel about > adding support for a new EPSG code, EPSG:0. > (if you want to review that discussion see here: > http://osgeo-org.1803224.n2.nabble.com/Generic-cartesian-CRS-code-zero-td6136122.html) > > ESPG:0 would represent pure cartesian data, lack of any referencing, and would > thus be associated to DefaultEngineeringCRS.GENERIC_2D, which is designed to > be > a lenient wildcard CRS, from the javadoc: >
+1 for me (though I can already see newbies being confused by it :-) > ---------------- > > A two-dimensional wildcard coordinate system with x, y axis in metres. > At the difference of CARTESIAN_2D, this coordinate system is treated > specially by the > default coordinate operation factory with loose transformation rules: > if no transformation > path were found (for example through a derived CRS), then the > transformation from this > CRS to any CRS with a compatible number of dimensions is assumed to be the > identity transform. This CRS is usefull as a kind of wildcard when no > CRS were explicitly specified. > > --------------- > > The only different would be that this one would be constructed so that it > reports being EPSG:0 as being its "name". > > The idea behind EPSG:0 is to be able to handle non georeferenced data, > or data that is expressed in some unkonwn coordinate system. > This would allow to natively handle CAD data in vector land and plain > images in raster land still using our GeoTools Feature/Coverage concepts, > and avoid users to try and force EPSG:4326 in it instead (because it's often > the only code they remember). > > As far as I can see this fits well with our existing code base, that already > uses in some places DefaultEngineeringCRS.GENERIC_2D when no > native CRS could be found, this work would just give it a name. > > Gabriel on the old thread raised a good point that the WMS 1.3 spec also has > CRS:1 as the identifier to be used for the same purpose. > I'm not going to go down that road because this would require making a large > amount of changes to many bits of existing code assuming the authority > is always going to be ESPG, both in GeoTools and GeoServer. > The day we go there and allow the library to function properly without those > assumption its going to be easy to add a further alias to that CRS > and have it respond as CRS:1 as well. > > To wrap up, I'd like to add a new authority factory in referencing that > adds support for that code and then check that base stores and coverage > readers are working properly with it. > Since this is an addition it's not going to break code not using it, > thus I propose to commit the changes on both trunk and 2.7.x > > Opinions? > > Cheers > Andrea > > -- > ------------------------------------------------------- > Ing. Andrea Aime > GeoSolutions S.A.S. > Tech lead > > Via Poggio alle Viti 1187 > 55054 Massarosa (LU) > Italy > > phone: +39 0584 962313 > fax: +39 0584 962313 > > http://www.geo-solutions.it > http://geo-solutions.blogspot.com/ > http://www.youtube.com/user/GeoSolutionsIT > http://www.linkedin.com/in/andreaaime > http://twitter.com/geowolf > > ------------------------------------------------------- > > ------------------------------------------------------------------------------ > WhatsUp Gold - Download Free Network Management Software > The most intuitive, comprehensive, and cost-effective network > management toolset available today. Delivers lowest initial > acquisition cost and overall TCO of any competing solution. > http://p.sf.net/sfu/whatsupgold-sd > _______________________________________________ > Geotools-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geotools-devel > -- Ian Turton ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
