+ double az1 = 0.0, az2 = 0.0, s = 0.0;
+ SGGeod geod = SGGeod::fromCart(aircraft);
+ geo_inverse_wgs_84( geod, station->get_pos(), &az1, &az2, &s);
+ az1 = az1 - station->get_multiuse();
+ if ( az1 > 180.0) az1 -= 360.0;
+ if ( az1 < -180.0) az1 += 360.0;
+ // penalize opposite facing stations by adding 5000 meters
+ // (squared) which is further than matching stations would
+ // ever be placed from each other.
+ if ( fabs(az1) > 90.0 ) {
+ double dist = sqrt(d2);
+ d2 = (dist + 5000) * (dist + 5000);
+ }
+ }
+
+ if ( d2 < min_dist ) {
+ min_dist = d2;
+ nav = station;
+ }
+ }
+
+ return nav;
+}
+
+
+// returns the closest entry to the give lon/lat/elev
+FGNavRecord *FGNavList::findClosest( double lon_rad, double lat_rad,
+ double elev_m, fg_nav_types type)
+{
+ FGNavRecord *result = NULL;
+ double diff;
+
+ double lon_deg = lon_rad * SG_RADIANS_TO_DEGREES;
+ double lat_deg = lat_rad * SG_RADIANS_TO_DEGREES;
+ int lonidx = (int)lon_deg;
+ diff = lon_deg - (double)lonidx;
+ if ( (lon_deg < 0.0) && (fabs(diff) > SG_EPSILON) ) {
+ lonidx -= 1;
+ }
+ lonidx += 180;
+
+ int latidx = (int)lat_deg;
+ diff = lat_deg - (double)latidx;
+ if ( (lat_deg < 0.0) && (fabs(diff) > SG_EPSILON) ) {
+ latidx -= 1;
+ }
+ latidx += 90;
+
+ int master_index = lonidx * 1000 + latidx;
+
+ const nav_list_type& navs = navaids_by_tile[ master_index ];
+ // cout << "Master index = " << master_index << endl;
+ // cout << "beacon search length = " << beacons.size() << endl;
+
+ nav_list_const_iterator current = navs.begin();
+ nav_list_const_iterator last = navs.end();
+
+ SGGeod geod = SGGeod::fromRadM(lon_rad, lat_rad, elev_m);
+ SGVec3d aircraft = SGVec3d::fromGeod(geod);
+
+ double min_dist = 999999999.0;