Re: [mapguide-users] MapGuide 2.X : Why Developers don't develop MapGuide to replace the local arbitrary SRS of DataSource by the SRS of the parent Map when we open a session ?
Don't worry Jackie, i understand without problem the SRS abitrary concept. Thanks for your reply, i will send this week a conceptual schema to explain more clearly why i do that. Remy - AG-Carto - Bayonne -- View this message in context: http://osgeo-org.1560.n6.nabble.com/MapGuide-2-X-Why-Developers-don-t-develop-MapGuide-to-replace-the-local-arbitrary-SRS-of-DataSource--tp5031537p5031616.html Sent from the MapGuide Users mailing list archive at Nabble.com.___ mapguide-users mailing list mapguide-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapguide-users
[mapguide-users] MapGuide 2.X : Why Developers don't develop MapGuide to replace the local arbitrary SRS of DataSource by the SRS of the parent Map when we open a session ?
Hi, Developper's MapGuide can tell me why MapGuide don't replace SRS DataSource automatically, when I use a data source with local arbitrary SRS with a Map which have a standard SRS Spatial, by the SRS of the Map ? I have a lot of DataSource SHP, SQLite which contain Data with different SRS and we use it without SRS. It's reducing considerably MapGuide Administrator task : 1 data source without SRS specified and 1 layer for all the Maps with different SRS To display in the Map it's Ok but when I want make some buffer or execute geometry API, it's bad... I understand that I need : - A data source with a standard or customize SRS and a map with a standard or customized SRS Or - A data source with a local arbitrary SRS and a map with a local arbitrary SRS But I ask the question again : why Developers don't develop MapGuide to replace the local arbitrary SRS of DataSource by the SRS of the parent Map when we open a session ? thanks for your answered Rémy ___ mapguide-users mailing list mapguide-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapguide-users
Re: [mapguide-users] MapGuide 2.X : Why Developers don't develop MapGuide to replace the local arbitrary SRS of DataSource by the SRS of the parent Map when we open a session ?
I hope you understand what an *arbitrary* SRS means. It's an SRS that has no real world context. The coordinates of your geometries cannot be determined on the surface of planet earth. Now for a Map to do its auto-magical re-projection of layers, the Map's coordinate system and the layer's coordinate system must be of the same type. It can't re-project a layer if it's data is based on arbitrary coordinates. Think of what I already said: Geometries in arbitrary SRS coordinates cannot be determined on the Earth's surface, so how could CS-Map possibly know what real world context from which to transform said layer's coordinates to the coordinate system of your Map? Okay, suppose your Feature Source has an arbitrary SRS, but you know what SRS the coordinates actually represent. Then this is where you can use the Coordinate System override mechanism in the Feature Source to replace the arbitrary SRS with a non-arbitrary one, allowing for the Map to re-project such data if required. The Coordinate System override is a hint to MapGuide as to how to interpret the coordinates from that Feature Source. It won't do any validation. For example, if you override your SRS with WGS84, MapGuide is not going to check that your coordinates must be within [-180, 180], [-90, 90]. If you're intentionally using your *geospatial* data with a local SRS, I'd really question why you must do this. Do you give SHP files to people without the .prj file? That's effectively what you're doing. - Jackie -- View this message in context: http://osgeo-org.1560.n6.nabble.com/MapGuide-2-X-Why-Developers-don-t-develop-MapGuide-to-replace-the-local-arbitrary-SRS-of-DataSource--tp5031537p5031593.html Sent from the MapGuide Users mailing list archive at Nabble.com. ___ mapguide-users mailing list mapguide-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapguide-users
