Milton Jonathan wrote: > Hello people > > I have a (common?) practical problem where I have spatial data (with > some attributes) on one side (e.g., a shapefile, or a spatial table in a > database), and a bunch of related information that's being stored > somewhere else (e.g., a regular table in a database that has an FID > column matching those in the spatial table). > > So I ask: what is the most usual way in GeoTools for "glueing" or > linking these two sets of data? Brute force and a for loop :-) If you need to join on spatial data take one data set and stuff the geometries in a JTS Spatial index to save time. If you can do it based on ID then a HashSet will be your friend.
If you check into the validation module you can see lots of painful slow examples of doing things this way. > table). I guess that, when everything is within a single database, one > can create a view that already joins these data beforehand, and the > feature source would then be that view. Or is there a better way of > doing this? > Correct; that is a common solution when the data is in the same database. > Anyway, I am not sure if this is really within the scope GeoTools > itself, but it looks like a very common problem and so maybe someone has > already thought of some mechanisms in GeoToools to help with that.. > > It is in scope and there have been a few attempts at solving it - but nothing successful so far. The author of JTS Topology Suite has a pretty interesting project in this regard (a small domain specific language that supports joins and stuff) - but you can go ask about that on the JTS email list cause I do not have the details. My best solution would be to load stuff into a local H2 database and hack away; but I am waiting for someone bright to add a spatial index to H2 before even trying that. Jody ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
