GeoJSON latitude lines not straight

I’m loading political borders as geojson, but I’m seeing that the 49th Parallel between the US and Canada is getting rendered as an arc in Cesium instead of as a straight line of latitude. My code is:
viewer.dataSources.add(Cesium.GeoJsonDataSource.load(’/Content/borders.json’, {

stroke: Cesium.Color.fromBytes(143, 188, 143, 255),

fill: Cesium.Color.BLACK.withAlpha(0.0),

strokeWidth: 1



My geojson file is just a set of LineStrings:



The two points that span the 49th Parallel are: [-123.307778,48.999722],[-95.236389,48.999722]

My guess is that Cesium is rendering the lines between points on a great circle instead of linearly by lat and lon. Am I missing a setting or property somewhere? (FYI, I’m a using Cesium 1.20)

Your guess is correct. This is a known issue that we plan on fixing see:

This was something that (I believe) the original GeoJSON spec was fuzzy on but the recently updated spec makes very clear.

We plan on having a bug bash in the near future, so anyone who is interested should +1 that issue on GitHub. I can’t promise we will get to it (though I personally want to see it fixed ASAP), but community feedback will help us set priorities.


Thanks for the quick reply! I’ll keep an eye on that issue.