postgis
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| Both sides previous revision Previous revision Next revision | Previous revision | ||
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postgis [2016/10/06 14:55] mantis |
postgis [2020/02/12 12:06] (current) mantis [Export table to geojson] |
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| ====== Enabling Postgis ====== | ====== Enabling Postgis ====== | ||
| - | |||
| - | I | ||
| ===== Ubuntu 16.04 (Postgres 9.5) ===== | ===== Ubuntu 16.04 (Postgres 9.5) ===== | ||
| Line 18: | Line 16: | ||
| ==== Create a PostGIS-enabled database ==== | ==== Create a PostGIS-enabled database ==== | ||
| - | and create a database using the template: | + | |
| <code sql> | <code sql> | ||
| Line 101: | Line 99: | ||
| ===== Update gis table registry ===== | ===== Update gis table registry ===== | ||
| - | In table spatial_ref_sys all tables containing PostGIS types are listed. | + | In table spatial_ref_sys, all tables containing PostGIS types are listed. |
| To refresh this cache: | To refresh this cache: | ||
| Line 118: | Line 116: | ||
| UPDATE mytable SET the_geom = ST_SetSRID(ST_MakePoint(longitude,latitude),4326); | UPDATE mytable SET the_geom = ST_SetSRID(ST_MakePoint(longitude,latitude),4326); | ||
| </code> | </code> | ||
| + | ===== Export table to geojson ===== | ||
| + | |||
| + | Building a FeatureCollection ([[https://postgis.net/docs/ST_AsGeoJSON.html|docs]], [[https://gist.github.com/brambow/889aca48831e189a62eec5a70067bf8e|code snippet]]): | ||
| + | |||
| + | <code sql> | ||
| + | SELECT json_build_object( | ||
| + | 'type', 'FeatureCollection', | ||
| + | 'crs', json_build_object( | ||
| + | 'type', 'name', | ||
| + | 'properties', json_build_object( | ||
| + | 'name', 'EPSG:4326' | ||
| + | ) | ||
| + | ), | ||
| + | 'features', json_agg( | ||
| + | json_build_object( | ||
| + | 'type', 'Feature', | ||
| + | 'id', id, | ||
| + | 'geometry', ST_AsGeoJSON(the_geom)::json, | ||
| + | 'properties', json_build_object( | ||
| + | 'name', name, | ||
| + | 'frc', frc, | ||
| + | 'fromjunction', fromjunction, | ||
| + | 'tojunction', tojunction, | ||
| + | ) | ||
| + | ) | ||
| + | ) | ||
| + | ) | ||
| + | FROM roadmap_table; | ||
| + | </code> | ||
| + | |||
| + | |||
| ===== Select all geometries in an area ===== | ===== Select all geometries in an area ===== | ||
| <code sql> | <code sql> | ||
postgis.1475758519.txt.gz ยท Last modified: 2016/10/06 14:55 by mantis
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