Polygon changing during projection

Question

Riddle me this.  I have a polygon (here ) when I query for it with no specific SRID everything looks fine.

Taking the same polygon and requesting it in 4326 appears to totally change the shape to encompass the world.  Here

Any ideas how to recognize this situation and avoid them?

Richard Howe · Answer

Does your polygon only have 4 vertices? Because  a re-projection only moves the vertices and still draws straight lines between them. I've seen this cause re-projection issues, like the one you describe, before. If you can densify the polygon, adding extra vertices along straight edges, you tend to get a better re-projection result.