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Stefan (Diskussion | Beiträge) (→Point Constructors) |
Stefan (Diskussion | Beiträge) (→Point Constructors) |
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== Point Constructors == | == Point Constructors == | ||
| − | Point | + | Point constructors for geometry and geography types: Howto construct and print a coordinate in EPSG:4326 and in lon/lat format in either textual or 'symbolic' form? |
| − | + | Works... | |
| − | + | /*1 */ SELECT ST_AsEWKT(ST_GeomFromText('POINT(-71.06 42.28)', 4326)) -- ok, preferred if text input | |
| − | + | /*2 */ SELECT ST_AsEWKT(ST_GeomFromText('SRID=4326;POINT(-71.06 42.28)')) -- ok (if srid 'inline') | |
| − | + | /*3 */ SELECT ST_AsEWKT(ST_GeomFromEWKT('SRID=4326;POINT(-71.06 42.28)')) -- ok, but why then ST_GeomFromText? | |
| − | + | /*4 */ SELECT ST_AsEWKT('SRID=4326;POINT(-71.06 42.28)'::geometry) -- ok, but prefer 1/ST_GeomFromText | |
| − | + | /*5 */ SELECT ST_AsEWKT(ST_SetSRID('POINT(-71.06 42.28)'::geometry, 4326)) -- ok, but prefer 1/ST_GeomFromText | |
| + | /*6 */ SELECT ST_AsEWKT(ST_MakePoint(-71.06, 42.28, 4326)) -- ok for 'symbolic' form. But why no EWKT returning? | ||
| − | + | Does not work...! | |
| − | + | /*1 */ SELECT ST_AsEWKT(ST_GeogFromText('POINT(-71.06 42.28)', 4326)) -- ERROR: unknown ST_GeogFromText(): why? | |
| − | + | /*2a*/ SELECT ST_AsEWKT(ST_GeogFromText('SRID=4326;POINT(-71.06 42.28)')) -- ERROR: no ST_AsEWKT: why not? | |
| − | + | /*2b*/ SELECT ST_AsText(ST_GeogFromText('SRID=4326;POINT(-71.06 42.28)')) -- ok (if srid 'inline'); no AsEWKT | |
| − | + | /*3 */ SELECT ST_AsText(ST_GeogFromEWKT('SRID=4326;POINT(-71.06 42.28)')) -- ERROR: no ST_GeogFromEWKT: why? | |
| − | + | /*4 */ SELECT ST_AsText('SRID=4326;POINT(-71.06 42.28)'::geography) -- ok (no AsEWKT), but prefer 1/ST_GeomFromText | |
| − | + | /*5 */ SELECT ST_AsText(ST_SetSRID('POINT(-71.06 42.28)'::geography, 4326)) -- ERROR: ok SetSRID w. geography unnecessary | |
| + | /*6 */ Equivalent to ST_MakePoint for geography types missing: => ST_MakePointG? | ||
Wishlist for future(!) PostGIS developments: | Wishlist for future(!) PostGIS developments: | ||
Version vom 16. Februar 2011, 15:19 Uhr
See also:
Inhaltsverzeichnis
Point Constructors
Point constructors for geometry and geography types: Howto construct and print a coordinate in EPSG:4326 and in lon/lat format in either textual or 'symbolic' form?
Works...
/*1 */ SELECT ST_AsEWKT(ST_GeomFromText('POINT(-71.06 42.28)', 4326)) -- ok, preferred if text input
/*2 */ SELECT ST_AsEWKT(ST_GeomFromText('SRID=4326;POINT(-71.06 42.28)')) -- ok (if srid 'inline')
/*3 */ SELECT ST_AsEWKT(ST_GeomFromEWKT('SRID=4326;POINT(-71.06 42.28)')) -- ok, but why then ST_GeomFromText?
/*4 */ SELECT ST_AsEWKT('SRID=4326;POINT(-71.06 42.28)'::geometry) -- ok, but prefer 1/ST_GeomFromText
/*5 */ SELECT ST_AsEWKT(ST_SetSRID('POINT(-71.06 42.28)'::geometry, 4326)) -- ok, but prefer 1/ST_GeomFromText
/*6 */ SELECT ST_AsEWKT(ST_MakePoint(-71.06, 42.28, 4326)) -- ok for 'symbolic' form. But why no EWKT returning?
Does not work...!
/*1 */ SELECT ST_AsEWKT(ST_GeogFromText('POINT(-71.06 42.28)', 4326)) -- ERROR: unknown ST_GeogFromText(): why?
/*2a*/ SELECT ST_AsEWKT(ST_GeogFromText('SRID=4326;POINT(-71.06 42.28)')) -- ERROR: no ST_AsEWKT: why not?
/*2b*/ SELECT ST_AsText(ST_GeogFromText('SRID=4326;POINT(-71.06 42.28)')) -- ok (if srid 'inline'); no AsEWKT
/*3 */ SELECT ST_AsText(ST_GeogFromEWKT('SRID=4326;POINT(-71.06 42.28)')) -- ERROR: no ST_GeogFromEWKT: why?
/*4 */ SELECT ST_AsText('SRID=4326;POINT(-71.06 42.28)'::geography) -- ok (no AsEWKT), but prefer 1/ST_GeomFromText
/*5 */ SELECT ST_AsText(ST_SetSRID('POINT(-71.06 42.28)'::geography, 4326)) -- ERROR: ok SetSRID w. geography unnecessary
/*6 */ Equivalent to ST_MakePoint for geography types missing: => ST_MakePointG?
Wishlist for future(!) PostGIS developments:
- Create ST_AsEWKT for geography and harmonize ST_AsText (depreciate with EWKT).
- Create ST_GeogFromEWKT for geography and harmonize ST_GeogFromText (depreciate with EWKT).
hstore
Key-Value data type.
Index
DROP INDEX planet_osm_point_tags; CREATE INDEX planet_osm_point_tags ON planet_osm_point USING gin (tags)
DROP INDEX planet_osm_point_tags2; CREATE INDEX planet_osm_point_tags2 ON planet_osm_point USING btree (tags) WHERE tags->'natural'='peak';
Statistics: Counting the different values in hstore
SELECT lower(tags->'cuisine') as tags, count(*) AS count FROM planet_osm_point WHERE tags ? 'cuisine' GROUP BY 1 ORDER BY 2 DESC; "regional";416 "italian";197 "pizza";123 "burger";112
SELECT count(*) AS c, cuisine FROM ( SELECT lower(tags->'cuisine') AS cuisine FROM planet_osm_point WHERE tags ? 'cuisine' UNION ALL SELECT lower(tags->'cuisine') AS cuisine FROM planet_osm_polygon WHERE tags ? 'cuisine' ) AS t GROUP BY cuisine ORDER BY c DESC;
