Categories:: Geospatial functions, Conversion functions

ST_GEOGFROMGEOHASH¶

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

The optional precision argument specifies the precision to use for the input geohash. For example, passing 5 for precision specifies that the function should use the first 5 characters of the input geohash.

See also:: ST_GEOHASH, ST_GEOGPOINTFROMGEOHASH

Syntax¶

ST_GEOGFROMGEOHASH( <geohash> [, <precision> ] ) 

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Arguments¶

Required:

geohash: The argument must be a geohash.

Optional:

precision

The number of characters to use from the input geohash. For example, passing 5 for precision causes the function to use the first 5 characters in the geohash.

You can specify a value from 1 to 20.

By default, precision is 20, which causes the function to use up to the first 20 characters of the geohash.

Returns¶

The function returns a value of type GEOGRAPHY.

Examples¶

The following example returns the GEOGRAPHY object for a geohash:

SELECT ST_GEOGFROMGEOHASH('9q9j8ue2v71y5zzy0s4q') AS geography_from_geohash, ST_AREA(ST_GEOGFROMGEOHASH('9q9j8ue2v71y5zzy0s4q')) AS area_of_geohash; +---------------------------------+-----------------+ | GEOGRAPHY_FROM_GEOHASH | AREA_OF_GEOHASH | |---------------------------------+-----------------| | { | 5.48668572e-16 | | "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" | | | } | | +---------------------------------+-----------------+ 

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The following example returns the GEOGRAPHY object for a less precise geohash. The function uses the first 6 characters from the input geohash:

SELECT ST_GEOGFROMGEOHASH('9q9j8ue2v71y5zzy0s4q', 6) AS geography_from_less_precise_geohash, ST_AREA(ST_GEOGFROMGEOHASH('9q9j8ue2v71y5zzy0s4q', 6)) AS area_of_geohash; +-------------------------------------+-----------------+ | GEOGRAPHY_FROM_LESS_PRECISE_GEOHASH | AREA_OF_GEOHASH | |-------------------------------------+-----------------| | { | 591559.75661851 | | "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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