As a newcomer to the Cesium visualization ecosystem, I find that I am confused when it comes to coordinate systems.
I see Cartesian used to describe x, y, z coordinates, but I don’t see anywhere that says whether they are Earth-centered Earth-fixed (ECEF) or Earth-centered inertial (ECI), or none of these. (If I had to guess, they’re ECEF.)
With geodetic coordinates, does Cesium convert these to ECEF coordinates?
Would this not imply that there are coordinate conversion utilities in the Cesium library? I cannot find these.
Note: I’m trying to visualize satellite trajectories.
Also, given this information, where would be the best place to document it for other newcomers?
Hey I found it!
This information is located in the CZML documentation (https://github.com/AnalyticalGraphicsInc/cesium/wiki/CZML-Content), not the Cesium documentation.
Although–there still should be a goedetic/cartographic to Cartesian conversion routine somewhere in Cesium, correct?
Hi Brian,
You want Ellipsoid.cartographicToCartesian and cartesianToCartographic.
Cartesian3 can be used to represent any 3D vector, so it can represent inertial coordinates, or an offset from a local reference frame, or any number of other things. But if the Cartesian3 represents a position, and it’s not clear from the context that the position means something else, you can generally assume it is ECEF.
Kevin