+ const nav_list_type& stations = navaids[(int)(freq*100.0 + 0.5)];
+
+ SGGeod geod = SGGeod::fromRadM(lon, lat, elev);
+ SGVec3d aircraft = SGVec3d::fromGeod(geod);
+ SG_LOG( SG_INSTR, SG_DEBUG, "findbyFreq " << freq << " size " << stations.size() );
+
+ return findNavFromList( aircraft, stations );
+}
+
+
+FGNavRecord *FGNavList::findByIdent( const char* ident,
+ const double lon, const double lat )
+{
+ const nav_list_type& stations = ident_navaids[ident];
+ SGGeod geod = SGGeod::fromRad(lon, lat);
+ SGVec3d aircraft = SGVec3d::fromGeod(geod);
+ return findNavFromList( aircraft, stations );
+}
+
+
+nav_list_type FGNavList::findFirstByIdent( const string& ident, fg_nav_types type, bool exact)
+{
+ nav_list_type n2;
+ n2.clear();
+
+ int iType;
+ if(type == FG_NAV_VOR) iType = 3;
+ else if(type == FG_NAV_NDB) iType = 2;
+ else return(n2);
+
+ nav_ident_map_iterator it;
+ if(exact) {
+ it = ident_navaids.find(ident);
+ } else {
+ bool typeMatch = false;
+ int safety_count = 0;
+ it = ident_navaids.lower_bound(ident);
+ while(!typeMatch) {
+ nav_list_type n0 = it->second;
+ // local copy, so we should be able to do anything with n0.
+ // Remove the types that don't match request.
+ for(nav_list_iterator it0 = n0.begin(); it0 != n0.end();) {
+ FGNavRecord* nv = *it0;
+ if(nv->get_type() == iType) {
+ typeMatch = true;
+ ++it0;
+ } else {
+ it0 = n0.erase(it0);
+ }
+ }
+ if(typeMatch) {
+ return(n0);
+ }
+ if(it == ident_navaids.begin()) {
+ // We didn't find a match before reaching the beginning of the map
+ n0.clear();
+ return(n0);
+ }
+ safety_count++;
+ if(safety_count == 1000000) {
+ SG_LOG(SG_INSTR, SG_ALERT,
+ "safety_count triggered exit from while loop in findFirstByIdent!");
+ break;
+ }
+ ++it;
+ if(it == ident_navaids.end()) {
+ n0.clear();
+ return(n0);
+ }
+ }
+ }
+ if(it == ident_navaids.end()) {
+ n2.clear();
+ return(n2);
+ } else {
+ nav_list_type n1 = it->second;
+ n2.clear();
+ for(nav_list_iterator it2 = n1.begin(); it2 != n1.end(); ++it2) {
+ FGNavRecord* nv = *it2;
+ if(nv->get_type() == iType) n2.push_back(nv);
+ }
+ return(n2);
+ }
+}
+
+
+// Given an Ident and optional freqency, return the first matching
+// station.
+FGNavRecord *FGNavList::findByIdentAndFreq( const char* ident, const double freq )
+{
+ nav_list_type stations = ident_navaids[ident];
+ SG_LOG( SG_INSTR, SG_DEBUG, "findByIdent " << ident<< " size " << stations.size() );
+ if ( freq > 0.0 ) {
+ // sometimes there can be duplicated idents. If a freq is
+ // specified, use it to refine the search.
+ int f = (int)(freq*100.0 + 0.5);
+ nav_list_const_iterator it, end = stations.end();
+ for ( it = stations.begin(); it != end; ++it ) {
+ if ( f == (*it)->get_freq() ) {
+ return (*it);
+ }
+ }
+ } else if (!stations.empty()) {
+ return stations[0];
+ }
+
+ return NULL;
+}
+
+
+// Given a point and a list of stations, return the closest one to the
+// specified point.
+FGNavRecord *FGNavList::findNavFromList( const SGVec3d &aircraft,
+ const nav_list_type &stations )
+{
+ FGNavRecord *nav = NULL;
+ double d2; // in meters squared
+ double min_dist
+ = FG_NAV_MAX_RANGE*SG_NM_TO_METER*FG_NAV_MAX_RANGE*SG_NM_TO_METER;
+
+ nav_list_const_iterator it;
+ nav_list_const_iterator end = stations.end();
+ // find the closest station within a sensible range (FG_NAV_MAX_RANGE)
+ for ( it = stations.begin(); it != end; ++it ) {
+ FGNavRecord *station = *it;
+ // cout << "testing " << current->get_ident() << endl;
+ d2 = distSqr(station->get_cart(), aircraft);
+
+ // cout << " dist = " << sqrt(d)
+ // << " range = " << current->get_range() * SG_NM_TO_METER
+ // << endl;
+
+ // LOC, ILS, GS, and DME antenna's could potentially be
+ // installed at the opposite end of the runway. So it's not
+ // enough to simply find the closest antenna with the right
+ // frequency. We need the closest antenna with the right
+ // frequency that is most oriented towards us. (We penalize
+ // stations that are facing away from us by adding 5000 meters
+ // which is further than matching stations would ever be
+ // placed from each other. (Do the expensive check only for
+ // directional atennas and only when there is a chance it is
+ // the closest station.)
+ int type = station->get_type();
+ if ( d2 < min_dist &&
+ (type == 4 || type == 5 || type == 6 || type == 12 || type == 13) )
+ {
+ double hdg_deg = 0.0;
+ if ( type == 4 || type == 5 ){
+ hdg_deg = station->get_multiuse();
+
+ } else if ( type == 6 ) {
+ int tmp = (int)(station->get_multiuse() / 1000.0);
+ hdg_deg = station->get_multiuse() - (tmp * 1000);