ST_M
Name
ST_M — Return the M coordinate of the point, or NULL if not available. Input must be a point.
Synopsis
    
     float
     
      ST_M
     
     (
    
    geometry
    
     a_point
    
    
     )
    
    ;
   
Description
Return the M coordinate of the point, or NULL if not available. Input must be a point.
       
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       This is not (yet) part of the OGC spec, but is listed here to complete the point coordinate extractor function list.  | 
    
   
    
   
   This method implements the
   
    OpenGIS Simple Features
 Implementation Specification for SQL 1.1.
   
  
   
    
   
   This method implements the SQL/MM specification.
  
   
    
   
   This function supports 3d and will not drop the z-index.