gistfile1.txt

#run this on your map of points
SELECT ST_Transform(ST_ConvexHull(ST_Collect(the_geom)),3857) AS the_geom_webmercator FROM my_spottings

(adjust)

#Change the style to Custom CartoCSS because now you need to apply a polygon style as you are no longer visualizing points


#my_spottings{
   polygon-fill:#FFCC00;
   polygon-opacity:0.49;
   line-opacity:0.49;
   line-color:#FF3366;
   line-width:2;
 }




In the future we will have mixed geometries in columns and you would not have to do some of this tricks.