ST_LATFROMGEOHASH

Description

The ST_LATFROMGEOHASH function is used to calculate and return the corresponding latitude value based on a given geohash string. This function can be widely used in map services, location queries, and geographic information systems.

Function Syntax

ST_LATFROMGEOHASH(hashstr)

Parameter Description

• hashstr (string): The geohash string for which the latitude needs to be calculated.

Return Result

Returns the calculated latitude value, with the data type being double.

Usage Example

1. Calculate the latitude value of a geohash string:

   SELECT ST_LATFROMGEOHASH('v0gs3y0z') as res;
   +-------------------+
   |        res        |
   +-------------------+
   | 50.00006675720215 |
   +-------------------+
   

2. Use in conjunction with other geographic information functions in query statements:

   SELECT ST_LATFROMGEOHASH(ST_GEOHASH(116.397428, 39.90923,3)) as res;
   +-----------+
   |    res    |
   +-----------+
   | 40.078125 |
   +-----------+
   

3. For batch calculation of latitude values for a set of geohash strings:

   SELECT ST_LATFROMGEOHASH('v0gs3y0z')as res1, ST_LATFROMGEOHASH('wh5g5jc3d') as res2, ST_LATFROMGEOHASH('4s7qfj9p0') as res3;
   +-------------------+--------------------+--------------------+
   |       res1        |        res2        |        res3        |
   +-------------------+--------------------+--------------------+
   | 50.00006675720215 | 23.059208393096924 | -64.87579107284546 |
   +-------------------+--------------------+--------------------+
   

Precautions

• Ensure that the input geohash string is valid, otherwise it may lead to inaccurate calculation results.
• When using this function, make sure that the relevant geographic information extension plugin is installed and enabled.

Through the above example, you can see that the ST_LATFROMGEOHASH function can conveniently extract latitude information from the geohash string, thereby providing convenience for geographic information systems and location services.