By default, the 2D mode uses a CartographicProjection
. When you place some circles at different latitudes, then this is the result:
They will only be “perfect circles” when they are shown at the equator.
In contrast to that, when you are using the WebMercatorProjection
, then it will look like this:
(Note that the size still appears to vary. There is no “right” way to map the surface of a sphere to a plane. There are only many different projections that are wrong in different ways…)
You can set that projection with
const viewer = new Cesium.Viewer("cesiumContainer", {
mapProjection: new Cesium.WebMercatorProjection()
});
Here is a sandcastle for the last screenshot: