Hi list, I am evaluating geotools to replace some "self made" code. Basically all I want to achieve is spatial filtering of points, linestrings and polygons. All geometries are based on points defined in lat/lon in various coordinate reference systems, and quite a lot of the geometries are quite "large", covering countries, continents,... As an additional quest there is "geometrical" metadata attached to some points, e.g. the line from point A to point B is a great circle, or a rhumbline, or a arc with point C as its center.
Now I create JTS geometries from this input data, ignoring the specified coordinate reference systems, taking lon lat values as lon lat values on a sphere, resulting in small inaccuracies. If there is geometrical metadata (great circle, rhumbline, arc..) attached, I calculate discretized points on the sphere. Then I apply spatial filtering with the unprojected lon lat values, as spatial filtering does not need a projection to work. I am facing big problems with polygons crossing the date line (from 180 W to 180 E and back again) as well as polygons that have a pole inside (something like Antarctica). If I understood the mail archived and the docs right, converting the input points to WGS84 or even better to a sphere based coordinate system should be no problem. Is geotools capable of calculating great circle, rhumblines and arcs on the sphere ? I've read in the archive that I have to project and reproject for this task, see http://sourceforge.net/mailarchive/forum.php?thread_id=30124078&forum_id=12232 Does spatial filtering work for shapes crossing the shapeline, and how do I have to create those shapes... if I have somthing like a rectangle with (10N170E, 10N170W, 10S170W, 10N170E) how would the appropiate geotools (jts ?) geometry look like (if i create a LINEARRING(10 170, 10 -170, -10 -170, -10 170, 10 170) there is obviously a self intersection ? And last but not leas the "polar" shapes.. something like a closed polygon with (170N 10W, 180N, 170W, 170N 10W), how can I implement this in geotools ? Thanks for every answer, greetings from Austria, Tom ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
