function lla2flat in R2020a

in the algorithm explanation of function lla2flat, the following equation is used:

Why is "atan" used in this equation? According to my knowledge delta arc length(metre) should be equal to angle(rad) by radius(metre).

Answer 1

[Gaurav Garg]

Hi,

You can look into the references for the function lla2flat for any information.

[宁宇 张]

This question is raised exactly because I looked into the reference. The equation is cited from the help document. I doubt that here the "atan" should not be used based on geometric calculation. Could you pls provide me further infomation to prove the correctness of this function? I guess maybe this is because of some algorithm or data type reasons that I dont know. Thank you very much in advance!