Categories:

Geospatial functions

ST_GEOMFROMGEOHASH

Returns a GEOMETRY object for the polygon that represents the boundaries of a geohash.

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:

ST_GEOHASH, ST_GEOMPOINTFROMGEOHASH

Syntax

ST_GEOMFROMGEOHASH( <geohash> [, <precision> ] )
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Arguments

Required:

geohash

The argument must be a geohash.

Optional:

precision

The number of characters to use in the geohash. You can specify a value from 1 to 20.

By default, precision is 20, 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;
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+---------------------------------+-----------------+ | 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;
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+------------------------------------+-----------------+ | 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" | | | } | | +------------------------------------+-----------------+
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