title: PostGIS - Create Ellipse
body: <p>Im trying to build a function to create an Ellipse without passing by classic programming language.
  I have these parameters stored in a custom GeoJSON.
  smallSide and bigSide has to be expressed in meters. Resulting geometry has to be created with EPSG 4326:</p>
  
  <p>My parameters are:</p>
  
  <pre><code> "geography" : {"type":"Ellipse",
                      "smallSide":100,
                      "bigSide" : 110,
                      "rotation" : 0,
                      "coordinates":[8.54736328125,46.37156925087649]}
  </code></pre>
  
  <p>Searching on web I found this solution that is very close to resolve my problem:</p>
  
  <pre><code>ST_AsEWKT(ST_Translate( ST_Rotate( ST_Scale( ST_Buffer(ST_Point(8.54736328125,46.37156925087649)::geography, 3000)::geometry, 0.3,0.5)::geometry, 0), 8.54736328125,46.37156925087649))
  </code></pre>
  
  <p>This function creates an Ellipse near Norway. Try with: <a href="http://geojson.io/#map=11/69.5354/11.1216" rel="nofollow noreferrer">http://geojson.io/#map=11/69.5354/11.1216</a></p>
  
  <p>The original center is in Switzerland.</p>
  
  <p>This function has 2 big problem:
  1. The Ellipse is not centered in the coords;
  2. I don't know how to convert xFactor/yFactor of Scale to match meters parameters;</p>
  
  <p>PS. This is the WKT of above function:</p>
  
  <pre><code>SRID=4326;POLYGON((11.123273576134 69.5574277440815,11.1230606869505 69.5547928070317,11.1224064250309 69.55225640052,11.1213360407351 69.5499159578464,11.1198907409861 69.547861360983,11.1181260946945 69.5461714955871,11.1161098932273 69.5449112303195,11.1139195487472 69.544128934906,11.1116391298573 69.5438546306632,11.1093561468668 69.5440988431489,11.1071582077927 69.5448522000687,11.1051296707337 69.5460857895281,11.1033484183676 69.5477522651534,11.1018828760511 69.5497876565102,11.100789386429 69.5521138166206,11.1001100408036 69.554641414163,11.099871051113 69.5572733570283,11.1000817266595 69.5599085170987,11.1007340973332 69.5624456140896,11.1018032006992 69.5647871095818,11.1032480248444 69.5668429613212,11.105013073265 69.5685340926073,11.107030493374 69.5697954420587,11.1092226874817 69.5705784748924,11.1115053053956 69.5708530575261,11.1137905020249 69.5706086220194,11.1159903323456 69.5698545746198,11.1180201503338 69.568619932341,11.1198018783021 69.5669522018393,11.1212670184877 69.5649155445927,11.1223592894673 69.5625883002992,11.1230367854657 69.5600599653373,11.123273576134 69.5574277440815))
  </code></pre>