On Wed, 2008-12-24 12:51:55 -0500, Michael Speth <[email protected]> wrote: > Some of you suggested using PostGIS for the problem that I'm trying to > solve. I think you guys are right. > You are also right that DB4O is not a good solution especially for embedded > applications. > > So my question is, does anyone know how I can access the database? I've > never used a spacial database but I do know how to open up connections and > write queries like Select.
A spa*t*ial database isn't really special in any way. You still use plain old SQL queries to access the data. The PostGIS extensions simply add some additional operators and functions to access the geometry columns. > Is there a way to access the database similar to how JOSM presents the data > (searching based on GPS coordinates)? Sure. To show some life example, this is the table I use for http://webcontent.osm.lab.rfc822.org/ : osm=> \d osm_webcontent Table "public.osm_webcontent" Column | Type | Modifiers -------------+----------+----------- node_id | bigint | not null bugtype | integer | not null description | text | geom | geometry | Indexes: "foorunkel" gist (geom) "index1" btree (node_id) Check constraints: "enforce_dims_geom" CHECK (ndims(geom) = 2) "enforce_geotype_geom" CHECK (geometrytype(geom) = 'POINT'::text OR geom IS NULL) "enforce_srid_geom" CHECK (srid(geom) = 4326) It contains point based information about specific locations. This is an example SQL query, SELECTing at max. 200 rows from that table, where the point (stored in the "geom" column) is within a given bounding box: osm=> select node_id, round(CAST(ST_X(geom) as numeric),7) as lon, round(CAST(ST_Y(geom) as numeric),7) as lat, description, bugtype from osm_webcontent where geom @ ST_SetSRID( ST_MakeBox2d( ST_MakePoint(8.2,47.5),ST_MakePoint(8.3,48)),4326) limit 200; MfG, JBG -- Jan-Benedict Glaw [email protected] +49-172-7608481 Signature of: Alles sollte so einfach wie möglich gemacht sein. the second : Aber nicht einfacher. (Einstein)
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