Introduction - If you have any usage issues, please Google them yourself
Serge white earth solvers, including the theme and counter-balance is operator. Calculating the distance by latitude and longitude, and latitude and longitude in accordance with that, the earth azimuth, calculate the length of geodesics another point latitude and longitude. Including his克拉索ellipsoid, 1975 International ellipsoid, WGS-84 ellipsoid can also be added in the code itself ellipsoid parameters.