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ST_GEOMFROMGEOHASH¶
Returns a GEOMETRY object for the polygon that represents the boundaries of a geohash (link removed).
The number of characters in a geohash determines precision. Removing characters from the end of a geohash results in a geohash that is less precise and that identifies a larger rectangular area.
The optional precision argument specifies the precision to use for the input geohash. For example, passing 5
for precision specifies that the function uses the first 5 characters of the input geohash.
- See also:
Syntax¶
ST_GEOMFROMGEOHASH( <geohash> [, <precision> ] )
Arguments¶
Required:
geohashThe argument must be a geohash.
Optional:
precisionThe number of characters to use in the geohash. You can specify a value from
1to20.By default,
precisionis20, which produces a geohash that is 20 characters long.
Returns¶
Returns a value of type GEOMETRY.
Examples¶
The following example returns the GEOMETRY object for a geohash:
SELECT ST_GEOMFROMGEOHASH('9q9j8ue2v71y5zzy0s4q')
AS geometry_from_geohash,
ST_AREA(ST_GEOMFROMGEOHASH('9q9j8ue2v71y5zzy0s4q'))
AS area_of_geohash;
+---------------------------------+-----------------+
| GEOMETRY_FROM_GEOHASH | AREA_OF_GEOHASH |
|---------------------------------+-----------------|
| { | 5.492996255e-26 |
| "coordinates": [ | |
| [ | |
| [ | |
| -1.223061000000001e+02, | |
| 3.755416199999996e+01 | |
| ], | |
| [ | |
| -1.223061000000001e+02, | |
| 3.755416200000012e+01 | |
| ], | |
| [ | |
| -1.223060999999998e+02, | |
| 3.755416200000012e+01 | |
| ], | |
| [ | |
| -1.223060999999998e+02, | |
| 3.755416199999996e+01 | |
| ], | |
| [ | |
| -1.223061000000001e+02, | |
| 3.755416199999996e+01 | |
| ] | |
| ] | |
| ], | |
| "type": "Polygon" | |
| } | |
+---------------------------------+-----------------+
The following example returns the GEOMETRY object for a less precise geohash. The function uses the first 6 characters from the input geohash:
SELECT ST_GEOMFROMGEOHASH('9q9j8ue2v71y5zzy0s4q', 6)
AS geometry_from_less_precise_geohash,
ST_AREA(ST_GEOMFROMGEOHASH('9q9j8ue2v71y5zzy0s4q', 6))
AS area_of_geohash;
+------------------------------------+-----------------+
| GEOMETRY_FROM_LESS_PRECISE_GEOHASH | AREA_OF_GEOHASH |
|------------------------------------+-----------------|
| { | 6.034970284e-05 |
| "coordinates": [ | |
| [ | |
| [ | |
| -1.223107910156250e+02, | |
| 3.755126953125000e+01 | |
| ], | |
| [ | |
| -1.223107910156250e+02, | |
| 3.755676269531250e+01 | |
| ], | |
| [ | |
| -1.222998046875000e+02, | |
| 3.755676269531250e+01 | |
| ], | |
| [ | |
| -1.222998046875000e+02, | |
| 3.755126953125000e+01 | |
| ], | |
| [ | |
| -1.223107910156250e+02, | |
| 3.755126953125000e+01 | |
| ] | |
| ] | |
| ], | |
| "type": "Polygon" | |
| } | |
+------------------------------------+-----------------+