I'm developing a webGIS website where I draw circles from two sources:
a mapserver mapfile that "draws" them from PostGIS (red circles in image). The circles are created with ST_Buffer, eg
ST_Buffer(ST_GeomFromText('POINT(A B)', 4326), 0.072414686825054, 'quad_segs=32')
My mapfile serves in 4326 and 3857.
Via Openlayers (blue concentric circles in image), either via
var wgs84Sphere = new ol.Sphere(6378137);
new ol.Feature(ol.geom.Polygon.circular(wgs84Sphere, GPS_pos_4326, i * 5 * 1852, 64).transform('EPSG:4326', 'EPSG:3857'));
or via turf, then creating an OL polygon, by using turf's destination function.
I understand that projecting a circle in "Google Mercator" should produce ellipses when not on the equator, so the behavior is expected.
But how could I do the same thing via OL?