Extensions
Scalar Functions
Returns a buffer around the input geometry at the target distance  
`geom` is the input geometry.  
`distance` is the target distance for the buffer, using the same units as the input geometry.  
`num_triangles` represents how many triangles that will be produced to approximate a quarter circle. The larger the number, the smoother the resulting geometry. The default value is 8.  
`join_style` must be one of "JOIN_ROUND", "JOIN_MITRE", "JOIN_BEVEL". This parameter is case-insensitive.  
`cap_style` must be one of "CAP_ROUND", "CAP_FLAT", "CAP_SQUARE". This parameter is case-insensitive.  
`mitre_limit` only applies when `join_style` is "JOIN_MITRE". It is the ratio of the distance from the corner to the mitre point to the corner radius. The default value is 1.0.  
This is a planar operation and will not take into account the curvature of the earth.  
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#### ST_Centroid {#docs:extensions:spatial:functions::st_centroid}