Currently we calculate the EGM correction by picking 4 points of the EGM96 grid and using a bilinear interpolation. https://github.com/BasicAirData/GPSLogger/blob/0d358e25a3d326c531bf4783b1e497a8e6b77684/app/src/main/java/eu/basicairdata/graziano/gpslogger/EGM96.java#L186 In order to have a better precision we should use the spline interpolation instead.
Currently we calculate the EGM correction by picking 4 points of the EGM96 grid and using a bilinear interpolation.
GPSLogger/app/src/main/java/eu/basicairdata/graziano/gpslogger/EGM96.java
Line 186 in 0d358e2
In order to have a better precision we should use the spline interpolation instead.