# Background The Muddy Map Explorer will support text-based exploration and navigation of map data, making it accessible to blind and visually disabled users. The user interface will be patterned after MUDs (Multi-User Domain games), REPLs (Read, Eval, Print Loops), etc. It will let users explore a mapped area at various scales, getting descriptions of streets, amenities, etc.
Using osm2pgsql, I've set up an exploratory database containing pretty much every possible relation and column, based on Geofabrik data on Texas and California (where my collaborator and I, respectively, live). So, I've got a nice pile of data to play with. However, I'm still a newbie at this, so I need help in developing some database queries. # Finding Nearby Ways Given a geographic location, it should be possible to find nearby ways, using only PostGIS and PostgreSQL. This would help us to get a working set of ways (and indirectly, nodes) for the user to explore. I found a few notions that seem tantalizingly close, but no exact matches: - Find nearest neighbours faster in PostGIS https://gis.stackexchange.com/questions/63667/find-nearest-neighbours-faster-in-postgis - How Do I Find The N Nearest Things To This Point In PostGis https://boundlessgeo.com/2011/09/indexed-nearest-neighbour-search-in-postgis - PostGIS / OSM: Faster query to find nearest line of points https://gis.stackexchange.com/questions/207592/postgis-osm-faster-query-to-find-nearest-line-of-points - Spatial Relationships and Measurements http://postgis.refractions.net/documentation/manual-svn/ST_DWithin.html Q: Is there an efficient way to find nearby ways for a location, using just PostgreSQL and/or PostGIS? # Tracking cities, etc. We'd like to be able to tell the user the current location, in human-friendly terms. Although we may know the starting location, traveling even a short distance could put the user into a different city, county, or country. We can't pester a geocoding service each time the user moves (and don't want to install and maintain Nominatim if we don't have to), so we need a local solution. A brute-force approach would be to look for nearby nodes that have TIGER (or equivalent) attributes. If the current location is "close enough" to a known address, that may be sufficient to our needs. Q: Is there an efficient way to get the administrative region for a location, using just PostgreSQL and/or PostGIS? -r -- http://www.cfcl.com/rdm Rich Morin [email protected] http://www.cfcl.com/rdm/resume San Bruno, CA, USA +1 650-873-7841 Software system design, development, and documentation _______________________________________________ dev mailing list [email protected] https://lists.openstreetmap.org/listinfo/dev
