Hi Richard,

Two of the main functions to caracterize geometries are :

- ST_AREA(the_geom) which compute the area of each geometries,

- ST_LENGHT(the_geom) which compute the length of each geometries,

- if your geometry is a point --> no result,

- if your geometry is a line --> you get the length of the line,

- if your geometry is a polygon --> you get the perimeter of the polygon.

So, in your case, you can test this instruction :

SELECT ST_LENGTH(the_geom) AS perimeter FROM mytable;

Regards,

Gwendall