PostGIS

问题 I'm using varnish in front of a tile server to cache mapbox tiles. To remove old tiles, I intended to use bans to effectively remove a large number of cached tiles. My problem is that varnish still uses the cached objects (at least the age in the response indicates this) and doesn't contact the backend. I'm first requesting http://varnish/5/3/4.pbf, then adding a ban with curl -X BAN -H 'X-Purge-Regex: 5/3/4.pbf' varnish or alternatively varnishadm and then ban obj.http.url ~ 5/3/4.pbf and

问题 I'm trying to return a queryset with distances from a related model. models.py (simplified) class Store(models.Model): geopoint = models.PointField(srid=4326) objects = models.GeoManager() class HashTag(models.Model): tag = models.CharField(max_length=100) class Label(models.Model): hashtags = models.ManyToManyField(HashTag) store = models.ForeignKey(Store) What I need to return are the Label objects which have a certain tag/tags ordered by distance from a given point. The Labels can be found

问题 I am trying this from hours now and I couldn't get get it solved. I am using this link to setup GeoDjango on Windows. I am getting following error message and I have no clue what to do. All the environment variables are set in Windows and I am able to import with from osgeo import gdal successfully in python terminal as import gdal is deprecated. In Postgresql database I have all extensions available as required like address_standardizer , fuzzystrmatch , ogr_fdw , pgrouting , plpgsql ,

问题 I am trying this from hours now and I couldn't get get it solved. I am using this link to setup GeoDjango on Windows. I am getting following error message and I have no clue what to do. All the environment variables are set in Windows and I am able to import with from osgeo import gdal successfully in python terminal as import gdal is deprecated. In Postgresql database I have all extensions available as required like address_standardizer , fuzzystrmatch , ogr_fdw , pgrouting , plpgsql ,

问题 I am trying to install Postgis in order to use GeoDjango on OSX. For this, I first uninstalled postgres completely, then I installed everything following the GeoDjango documentation: https://docs.djangoproject.com/en/dev/ref/contrib/gis/install/#homebrew I did the following: brew update brew upgrade brew install postgresql brew install postgis brew install gdal brew install libgeoip When I run my Django project, I get the following error: OSError at / dlopen(/usr/local/lib/libgeos_c.so, 6):

问题 I am trying to install Postgis in order to use GeoDjango on OSX. For this, I first uninstalled postgres completely, then I installed everything following the GeoDjango documentation: https://docs.djangoproject.com/en/dev/ref/contrib/gis/install/#homebrew I did the following: brew update brew upgrade brew install postgresql brew install postgis brew install gdal brew install libgeoip When I run my Django project, I get the following error: OSError at / dlopen(/usr/local/lib/libgeos_c.so, 6):

问题 I have two polygon layers. I want to run st_intersection on them, to give the result of the areas where they overlap as a new layer. The new layer should contain the attributes from both input layers. I found this image which seems to illustrate my desired end results. My two input layers are both polygons: SELECT st_geometrytype(geom), COUNT(*) FROM a GROUP BY st_geometrytype(geom) -- Result is 1368 st_polygons SELECT st_geometrytype(geom), COUNT(*) FROM b GROUP BY st_geometrytype(geom) --

问题 I'm using python 3.6 and postgres DB I have a table name: test_table with the following fields: name ( text ), geo ( geometry ) the srid of geo field is 32636 I want to write a python function which get point X (wkt) and return point Y with distance of 10 meters between the points. i.e: The X and Y are in WKT format How can I calculate the point Y with X is the input ? It seems that I can't use euclidean distance , because the srid is 32636 so how can I do it ? 回答1: You could cast your

问题 I have the following wtk: POLYGON((0 0, 10 0, 10 11, 11 10, 0 10)) In boost::geometry we can get this polygon representation using boost::geometry::dsv(polygon," "," "," "); How I can apply postgis st_makevalid function to a boost::geometry polygon? I suppose it something like: #include "libpq/libpq-fs.h" #include "../libpq-fe.h" . . . std::string geom = "POLYGON" + boost::geometry::dsv(multipoly," "," "," "); res = PQexecParams(conn, "SELECT st_makevalid(geom) FROM .... I do not want to

问题 I have this code. const char * q = "INSERT INTO test_raster (raw_data) VALUES (ST_SetValues(ST_AddBand(ST_MakeEmptyRaster(2, 2, -180, -90, 180, -90, 0, 0, 4326), 1, '8BUI', 0, 0), 1, 1, 1, $1::double precision[][]))"; double tmp[2][2] = { {0, 125}, {45, 255} }; const char *values[1] = { (char *)&tmp }; int lengths[1] = { 4*sizeof(double) }; int binary[1] = { 1 }; PGresult *rs = PQexecParams(psql, q, 1, NULL, values, lengths, binary, 0); auto stat = PQresultStatus(rs); printf("%s",