add inverse transforms

modules/util/geos_nav.py

@@ -203,8 +203,8 @@ class GEOSNavigation:
         s_3 = s_n * np.sin(y)
         s_xy = np.sqrt(s_1 * s_1 + s_2 * s_2)
 
-        geographic_lon = np.atan(s_2 / s_1) + self.sub_lon
-        geographic_lat = np.atan(fp * (s_3 / s_xy))
+        geographic_lon = np.arctan(s_2 / s_1) + self.sub_lon
+        geographic_lat = np.arctan(fp * (s_3 / s_xy))
 
         geographic_lon *= RAD_TO_DEG
         geographic_lat *= RAD_TO_DEG