PostGIS

问题 In PostgreSQL 9 + PostGIS 1.5, is there a way to create a "generic" GEOGRAPHY column? By that I mean a column that would accept POINTs as well as POLYGONs, LINESTRINGs, etc. Until now, I've only seen columns like GEOGRAPHY(POINT,4326) on the Internet. If that is not possible, then how would you design (from a DB point of view) an entity that is linked to a random geographical object (point, polygon, whatever)? Should I create 3, 4, 5 different tables for each type of geographical object I'd

问题 I have a simple table called"imposm3_restaurant" with columns [ id, name, geometry] I want to convert these data into geoJSON, I am using this function CREATE VIEW imposm3_restaurants_geojson AS SELECT row_to_json(fc) AS geojson FROM (SELECT 'FeatureCollection' As type, array_to_json(array_agg(f)) As features FROM (SELECT 'Feature' As type, ST_AsGeoJSON((lg.geometry),15,0)::json As geometry, row_to_json((id, name)) As properties FROM imposm3_restaurants As lg) As f ) As fc; and the result is

问题 Related, preceding question: Select a random entry from a group after grouping by a value (not column)? My current query looks like this: WITH points AS ( SELECT unnest(array_of_points) AS p ), gtps AS ( SELECT DISTINCT ON(points.p) points.p, m.groundtruth FROM measurement m, points WHERE st_distance(m.groundtruth, points.p) < distance ORDER BY points.p, RANDOM() ) SELECT DISTINCT ON(gtps.p, gtps.groundtruth, m.anchor_id) m.id, m.anchor_id, gtps.groundtruth, gtps.p FROM measurement m, gtps

问题 I'm trying to run a simple query in Hibernate Spatial 4.0 on PostgreSQL 9.3. I have a number of objects in a table with latitude/longitude values, and I'm trying to query objects that fall within a given radius of a particular latitude/longitude. The geometry values seem to be persisted without any problem, and are defined like this in my entity class: @Column(columnDefinition = "Geometry", nullable = true) @Type(type = "org.hibernate.spatial.GeometryType") private Point coordinates = null; I

问题 I upgraded and subsequently reinstalled PostGIS & PostgreSQL on OS X Mountain Lion. When trying to use the PostGIS extensions, I receive the following error: ERROR: could not open extension control file "/usr/local/Cellar/postgresql/ 9.2.3/share/postgresql/extension/postgis.control": No such file or directory It appears that PostGIS (and PostgreSQL as well??) are still looking for the required files in the /postgresql/9.2.3/ directory and not in the /postgresql/9.2.4/ directory. I have used

问题 I have a GIS API based on OpenLayers. I have been trying to implement Azimuth calculation in JavaScript and I needed some way to calculate the Azimuth in order to perform tests. I started using PostGIS, but there seem to be many ways to calculate the Azimuth between two points. I show you three of them and, some return different results. -- Example 1 - Result 90 SELECT ST_Azimuth( ST_Transform(st_geomfromtext('POINT(-81328.998084106 7474929.8690234)', 900913), 4326), ST_Transform(st

问题 I'm learning GIS with PostGIS and I wanted to try something funny so I downloaded shape files from OSM, imported in PostGres with PostGIS extension and now I want to represent data from PostGIS visually. I have Pulled data with Query SELECT ST_AsGeoJSON(geom) FROM "dar-es-salaam_tanzania.land_coast; I got bunch of GeoJSON and wanted to show them to user. Unfortunately it does not show it. I use Yii2 to write codes that pulls the data. Here is the controller code: public function actionIndex()

问题 I am transforming a shapefile by adding a new column attributes. Since this task is performed using Java, the only option I know for now is using Geotools. I have 2 main concerns: 1. I am not able to figure out how do I actually add a new column variable. Is the feature.setAttribute("col","value") the answer? I see from this post just the example:https://gis.stackexchange.com/questions/215660/modifying-feature-attributes-of-a-shapefile-in-geotools but I dont get the solution. //Upload the

问题 I am transforming a shapefile by adding a new column attributes. Since this task is performed using Java, the only option I know for now is using Geotools. I have 2 main concerns: 1. I am not able to figure out how do I actually add a new column variable. Is the feature.setAttribute("col","value") the answer? I see from this post just the example:https://gis.stackexchange.com/questions/215660/modifying-feature-attributes-of-a-shapefile-in-geotools but I dont get the solution. //Upload the

问题 A library I’m trying to use takes a given latitude and longitude and work out with entries in a table have a lat/lng within a certain distance from this. The generated SQL query works with MySQL, but not with PostgreSQL. Here’s the entry in my server.log file detailing the error psql is giving and the full query: ERROR: column "distance" does not exist at character 507 STATEMENT: select *, ( '3959' * acos( cos( radians('53.49') ) * cos( radians( places.lat ) ) * cos( radians( places.lng ) -