different projections

i assume the cesium globe needs 4326 as projection for displaying data.

i tried one ArcGIS service which has a different projection and is not drawn on the cesium globe. I did the same exercise with a service in 4326 and perfectly drawn around the globe.

my conclusion is that the projections matters and of course it does.
does the Cesium.ArcGisMapServerImageryProvider has a property where i can set the output spatial reference? I assume the Cesium object uses exportmap-function for retrieving the picture to be drawn on the globe.

In the Esri ArcGIS Rest interface there is a property for exportmap (imageSR) where you can set the requested spatial reference. I think if i can use this property inside the Cesium-object the issue I have right now will be resolved.

Start with Cesium.ArcGisMapServerImageryProvider and inspect how it builds the ArcGIS exportMap request. Compare the request behavior for services using EPSG:4326 and other projections, then verify the provider can request imagery in the needed spatial reference and display it on the globe. Confirm the result with an ArcGIS service that previously failed to render.

Written by the indexing model from the issue text.