In a previous life I had to implement conversions between ECEF and WGS84. If you do it, make sure to use at least 64-bit floats, the Earth is so big that 32-bit arithmetic will introduce errors on the order of meters.
You’ve brought memories of dealing with NAD83 (for local maps) and WGS84 (for everything else) crashing back. The error between those is tiny at the distances I was dealing with, but it was enough that it bothered me.
“I’ll just automate this mapping task in Python, how bad could it be?”
In a previous life I had to implement conversions between ECEF and WGS84. If you do it, make sure to use at least 64-bit floats, the Earth is so big that 32-bit arithmetic will introduce errors on the order of meters.