Adding function to produce a great circle between two points.

scripts-available/CDB_GreatCircle.sql

@@ -0,0 +1,30 @@
+-- Return a line for the Great Circle between two points
+--
+-- start_point geometry : The origin of the line
+-- end_point   geometry : The distination of the line
+-- retruns     geometry
+create or replace function CDB_GreatCircle(start_point geometry ,end_point geometry ) RETURNS geometry as
+$$
+DECLARE
+	line geometry;
+BEGIN
+
+line = ST_Segmentize(
+         ST_Makeline(
+           start_point,
+           end_point
+         )::geography,
+         100000
+     )::geometry;
+
+if ST_XMax(line) - ST_XMin(line) > 180 then
+
+	line = ST_Difference(
+    ST_Shift_Longitude(line), ST_Buffer(ST_GeomFromText('LINESTRING(180 90, 180 -90)',4326), 0.00001));
+end if;
+
+
+return line;
+
+END $$
+LANGUAGE 'plpgsql'