GeoJSON latitude lines not straight

CesiumJS
1

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:

{“type”:“FeatureCollection”,“features”:[{“type”:“Feature”,“properties”:{“id”:“0”,“level”:1},“geometry”:{“type”:“LineString”,“coordinates”:[[79.003889,33.771667],[79.019444,33.753889],…]}},
{“type”:“Feature”,“properties”:{“id”:“1”,“level”:1},“geometry”:{“type”:“LineString”,“coordinates”:[[-69.499722,-17.505278],[-69.490833,-17.630278],…

``

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)

2

Your guess is correct. This is a known issue that we plan on fixing see: https://github.com/AnalyticalGraphicsInc/cesium/issues/4000

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

3

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