Thanks a lot, Martin. Where do you envision the database of identifier codes living? I know in GDAL, we typically read from a directory full of CSV's[1] that holds several thousand (not sure of the exact number right now) codes along with their transformations.
Adam [1] https://svn.osgeo.org/gdal/trunk/gdal/data/ On Thu, Aug 29, 2013 at 6:32 PM, Martin Desruisseaux < [email protected]> wrote: > Hello all > > There is a quick update on current work: > > "IdentifiedObject" is a type defined by the ISO 19111 specification. > "AbstractIdentifiedObject" [1] is the proposed SIS implementation. This > class is intended to be the base class of almost everything related to > Coordinate Reference System (GeographicCRS, ProjectedCRS, etc.). For this > reason, it would be an important class of SIS. > > The problem that "IdentifiedObject" tries to resolve is that the same map > projections are often known by different names and identifiers depending on > the providers. For example "Oblique Mercator" and "Hotine Oblique Mercator" > (in EPSG naming) are two different projections. But "Oblique Mercator" (not > Hotine) in EPSG naming is also called "Hotine Oblique Mercator Azimuth > Center" by ESRI, while "Hotine Oblique Mercator" (EPSG naming) is called > "Hotine Oblique Mercator Azimuth Natural Origin" by ESRI. In summary, it is > not sufficient to know the name of a map projection. We also need to know > who chosen that name (the "authority"). > > So IdentifiedObject manages: > > * A primary name (whatever SIS chooses as our preferred naming) > * An arbitrary amount of aliases, together with their authorities > * An arbitrary amount of identifiers, typically primary keys in a > database (e.g. "EPSG:4326"), again with the authority that defines > each identifier. > > > Martin > > > [1] https://builds.apache.org/job/**sis-jdk7/site/apidocs/org/** > apache/sis/referencing/**AbstractIdentifiedObject.html<https://builds.apache.org/job/sis-jdk7/site/apidocs/org/apache/sis/referencing/AbstractIdentifiedObject.html> > >
