I don't understand this. Tom, I thought we agreed that latitude and longitude are well established concepts? They don't have to mean the earth is round, but for centuries the Royal Navy used them to navigate, and we have well established measurements of latitudes and longitudes.
Some conclusions that I would expect you to agree with:
- Latitude indicates the angle the sun makes from the azimuth at noon on the equinox, and is 90 degrees minus the angle from azimuth to the north star (when visible, and corrected for the north star's slight offset from true north)
- Longitude indicates time offset from Greenwich Mean/UTC - 15 degrees per hour. 0 degrees longitude is where the sun is highest in the sky at noon UTC (except for the analemma of course)
I presented to you books from the Royal Navy on how to do latitude and longitude measurements based on the sun, stars, and moon from 150+ years ago, and books with tables of the latitudes and longitudes of many places around the world, and with logbooks from e.g. Captain Cook's voyages showing latitude/longitude measurements just about every day.
Do we not agree that latitude and longitude correspond to positions of the sun?