www.spatialreference.org (será actualizado ?)
Fred. On Tue, Jun 15, 2010 at 2:29 PM, Miguel Marques <[email protected]>wrote: > Boa tarde, > > > > Aproveitando o tópico de sistemas EPSG, há algum local que tenha a lista > actualizada dos códigos EPSG para os sistemas de coordenadas Portugueses, > activos e obsoletos? > > > > No site do > IGP<http://www.igeo.pt/produtos/Geodesia/Inf_tecnica/sistemas_referencia/sistemas_referencia.htm>encontrei > a referência e descrição dos sistemas de coordenadas, mas não o > código EPSG. > > > > Encontrei também um post no blog > Geo-divagações<http://geodivagar.blogspot.com/2009/11/codigos-epsg-utilizados-em-portugal.html>com > um resumo de Novembro do ano passado, mas que colide com uns e-mails > trocados nesta lista sobre os códigos EPSG há uns meses atrás, sobre os > Açores. > > > > Se alguém puder confirmar ou corrigir, agradeço. > > > > Miguel Marques > > > > > > *De:* [email protected] [mailto: > [email protected]] *Em nome de *Artur Gil > *Enviada:* segunda-feira, 14 de Junho de 2010 23:11 > *Para:* [email protected] > *Cc:* [email protected] > *Assunto:* [Portugal] OpenGeo announced the launch of the prj2epsg.orgtool > and website > > > http://blog.opengeo.org/2010/06/14/prj2epsg/ > > > Prj2EPSG > > June 14th, 2010 > > Once upon a time, a group of smart people got together to define a common > standards base for geographic map services, a “Web Map > Service<http://www.opengeospatial.org/standards/wms>” > specification, if you will. > > They wanted their map services to be interoperable, but different maps can > be rendered using > differentprojections<http://en.wikipedia.org/wiki/Map_projection>, > and in order to overlay one map onto another, they needed to know (and > advertise) the projections of both. > > There was an existing standard for representing map projections, called > “well-known > text<http://en.wikipedia.org/wiki/Well-known_text#Spatial_reference_systems>” > (which is also, confusingly, the name that describes a standard for > representing geometries) but it was quite verbose. Who, after all, could > remember this: > > GEOGCS["WGS 84", > > DATUM["WGS_1984", > > SPHEROID["WGS 84",6378137,298.257223563, > > AUTHORITY["EPSG","7030"]], > > AUTHORITY["EPSG","6326"]], > > PRIMEM["Greenwich",0, > > AUTHORITY["EPSG","8901"]], > > UNIT["degree",0.01745329251994328, > > AUTHORITY["EPSG","9122"]], > > AUTHORITY["EPSG","4326"]] > > More importantly, how would this fit cleanly into a URL? > > Fortunately, there already existed a large database of commonly used map > projections: the EPSG database <http://www.epsg.org/CurrentDB.html>. This > provided a single numeric ID for each common map projection. So it was > decided that all map services must advertise their projection using a unique > number defined by an authority, and set EPSG as the first authority. And so > ESPG:4326 came into the world (WGS84 geographic coordinates) along with > ESPG:26910 (NAD83 UTM Zone 10 North), and many others. > > But, unlike me, most GIS practitioners haven’t memorized the EPSG database. > So they frequently ask questions like *“what is the EPSG number for Oregon > State-Plane South?”* and *“how do I find the EPSG number for this > shapefile?”* One could search spatialreference.org, a site for > understanding spatial reference systems. My own answer used to be a fairly > unhelpful set of directions for doing a text search of the PostGIS > SPATIAL_REF_SYS table: > > SELECT srid, srtext FROM spatial_ref_sys WHERE srtext ILIKE '%oregon%'; > > But today, I can provide a much simpler answer: *Use > prj2epsg.org<http://prj2epsg.org/search> > *. With *prj2epsg.org <http://prj2epsg.org/search>*, you can paste in full > well-known text > descriptions<http://prj2epsg.org/search?terms=PROJCS%5B%22NAD_1983_StatePlane_Oregon_South_FIPS_3602_Feet_Intl%22%2CGEOGCS%5B%22GCS_North_American_1983%22%2CDATUM%5B%22D_North_American_1983%22%2CSPHEROID%5B%22GRS_1980%22%2C6378137.0%2C298.257222101%5D%5D%2CPRIMEM%5B%22Greenwich%22%2C0.0%5D%2CUNIT%5B%22Degree%22%2C0.0174532925199433%5D%5D%2CPROJECTION%5B%22Lambert_Conformal_Conic%22%5D%2CPARAMETER%5B%22False_Easting%22%2C4921259.842519685%5D%2CPARAMETER%5B%22False_Northing%22%2C0.0%5D%2CPARAMETER%5B%22Central_Meridian%22%2C-120.5%5D%2CPARAMETER%5B%22Standard_Parallel_1%22%2C42.33333333333334%5D%2CPARAMETER%5B%22Standard_Parallel_2%22%2C44.0%5D%2CPARAMETER%5B%22Latitude_Of_Origin%22%2C41.66666666666666%5D%2CUNIT%5B%22Foot%22%2C0.3048%5D%5D>, > you can type in shorter keyword > searches<http://prj2epsg.org/search?terms=bc+albers>, > and you can even read a .prj file directly. > > This free public service is provided by OpenGeo <http://opengeo.org/> and > our cloud services provider SkyGone <http://www.skygoneinc.com/>. The code > is naturally all open source <http://svn.opengeo.org/prj2epsg/trunk/> and > the service is built on top of the same GeoTools library that is at the > heart of ourOpenGeo Suite <http://opengeo.org/products/suite>. > > And now we’re all hopefully one step closer to living happily ever after. > > Tags: epsg <http://blog.opengeo.org/tag/epsg/>, > prj<http://blog.opengeo.org/tag/prj/> > , shapefile <http://blog.opengeo.org/tag/shapefile/>, > site<http://blog.opengeo.org/tag/site/> > , well known text <http://blog.opengeo.org/tag/well-known-text/>, > wkt<http://blog.opengeo.org/tag/wkt/> > > This entry was written by Paul Ramsey on Monday, June 14th, 2010 at 10:00 > am and is filed under Products<http://blog.opengeo.org/category/products/>. > You can follow any responses to this entry through the RSS > 2.0<http://blog.opengeo.org/2010/06/14/prj2epsg/feed/> feed. > You can leave a > response<http://blog.opengeo.org/2010/06/14/prj2epsg/#respond>, > or trackback <http://blog.opengeo.org/2010/06/14/prj2epsg/trackback/> from > your own site. > > > > > _______________________________________________ > Portugal mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/portugal > >
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