What is the verified surface curvature over the center of South Louisiana, who documented it and does it conform to a sphere with a 25,000 mile circumference?
How can elevations (vertical distances) from sea level show if the sea level itself is curved or not?
Are you still refusing to learn what is DATUM?
What is the verified surface curvature over the center of South Louisiana, who documented it and does it conform to a sphere with a 25,000 mile circumference?
It is confirmed by Datum definitions, including:
NAD 27 CONUS - North American Datum of 1927 for the Continental United States (Common on older USGS maps)
NAD 83 – North American Datum of 1983 (Used on most newer USGS maps)
WGS 84 – World Geodetic System of 1984 (The default datum used by the GPS system)
I believe the elevations in the map you posted were measured relative to NAD 83.
Now:
From Vinton, LA to Slidell, LA is 367 km, which is 198 nautical miles.
198 / 60 = 3.3
The curvature at that distance is 3.3 degrees.
Lafayette is "not far" from the center of that arc.
(Actually 150 km from Vinton and 217 from Slidell.)
The city is some 11 meters above the elevation at which "the sea would be if the land mass was removed".
The local land elevation says nothing about the shape of it, but the datum itself does.
I repeat:
Learn what is DATUM, please.BTW, if 3.3 degrees is 367 km, then 360 degrees is
367 / 3.3 x 360 = 40 036 km, which is 24 878 statute miles (0.5% less than 25 000 miles).