pl elevation functions

CREATE OR REPLACE FUNCTION public.dbs_ned_z(
    IN text,
    IN text,
    OUT text)
  RETURNS text AS
$BODY$
#!/bin/sh
url="http://ned.usgs.gov/epqs/pqs.php?output=json&x=$1&y=$2"; /usr/bin/curl -s $url
$BODY$
  LANGUAGE plsh VOLATILE
  COST 100;
  
  
  CREATE OR REPLACE FUNCTION public.dbs_point_elevation(
    IN geometry,
    OUT double precision)
  RETURNS double precision AS
$BODY$ SELECT (dbs_ned_z(st_x($1)::text,st_y($1)::text)::json->'USGS_Elevation_Point_Query_Service'->'Elevation_Query'->>'Elevation')::float8;$BODY$
  LANGUAGE sql VOLATILE
  COST 100;