Wednesday, 9 October 2019

convert - Conversion between lat/lon and local coordinate system


This is an example situation


I have local coordinate system, this is the red grid on the image. Red grid XY points measured in meters, and I know:




  • The 0;0 point of the red grid and the lat/lon coordinates of this one point. (the geo system is the green lines on the image measured in lat/lon). This is the one and only point I know values on booth coordinate system (the blue point on the image).




  • The angle of local coordinate system relative to latitude in degree.





Is it possible the convert values between these two coordinate system with a math formula? If I know the lat/lon values of the point on the green grid, can I get the XY values on the reg grid, and if I know the XY values of any point (and the angle of reg grid in deg) on the red grid in meters, can I got the lat/lon values on the geo coordinate system?


How can I get the transformation formula - if it even possible?


-------------- EDITED ---------------


Thinking how to solve this problem.




  • Convert lat/lon values of the common point (X Y) and the another (unknown) point from lat/lon to X1 Y1 values. This is the method to get same unit (meters) for different coordinate systems.





  • Count the difference between X1 - X and Y1 - Y to get vertical and horizontal distances between common point and the original lat/lon values.




  • Finally I can use formula from this page: https://en.wikipedia.org/wiki/Rotation_matrix but the angle is 90 - (my rotation angle from latitude) in degrees.




Is it right way?





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