Great arcs in CartoDB PostGIS

README.md

Make great arcs between two points.

From @andrewxhill: http://gis.stackexchange.com/questions/84443/what-is-this-postgis-query-doing-to-show-great-circle-connections

select-query.sql

SELECT ST_Transform(
	ST_Segmentize(
	  ST_MakeLine(
	    ST_Transform(CDB_LatLng(source_lat, source_lng), 953027),
	    ST_Transform(ST_PointOnSurface(CDB_LatLng(target_lat, target_lng)),953027)
	  ), 100000
	), 3857) as the_geom_webmercator
	
FROM table

update-query.sql

UPDATE my_table
SET the_geom =
   ST_Transform(
     ST_Segmentize(
       ST_MakeLine(
         ST_Transform(my_table.the_geom, 953027),
         ST_Transform(CDB_LatLng(48.432044, -71.060316), 953027)
       ), 
       100000
     ), 
    4326 
   )