Hi, I have tables of geometrical objects, with Latitude/Longitude coordinates, and we'd like to filter that data by **countries**. Given a set of polygons for countries, and [SQLite's GeoPoly](https://www.sqlite.org/geopoly.html) extension, it seems like this should be relatively easy. 1) Has anyone done that, and could share experience? 2) Where did you get the country boudaries? At which resolution? 3) Can the *lat/lon is within country X* be done efficiently using indexes? Perhaps an R-Tree index, for pre-filtering? 4) For *borderline* lat/lon, can nearby countries be returned as well? 5) How about perform? What should I watch out for? At this point, I'm just looking for community advise before diving into this myself, as I'm never used R-Tree and GeoPoly with SQLite. TIA, --DD