From: daveluff <daveluff>
Date: Tue, 11 Mar 2003 13:24:35 +0000 (+0000)
Subject: Added a function to return the closest ATC station of a given type
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=0333c21bbf30aa171ff297670bfa214ef948901a;p=flightgear.git

Added a function to return the closest ATC station of a given type
---

diff --git a/src/ATC/commlist.cxx b/src/ATC/commlist.cxx
index 8f282ea3b..36c5f88b5 100644
--- a/src/ATC/commlist.cxx
+++ b/src/ATC/commlist.cxx
@@ -209,6 +209,52 @@ int FGCommList::FindByPos(double lon, double lat, double elev, double range, com
 }
 
 
+// Returns the distance in meters to the closest station of a given type,
+// with the details written into ATCData& ad.  If no type is specifed simply
+// returns the distance to the closest station of any type.
+// Returns -9999 if no stations found within max_range in nautical miles (default 100 miles).
+// Note that the search algorithm starts at 10 miles and multiplies by 10 thereafter, so if
+// say 300 miles is specifed 10, then 100, then 1000 will be searched, breaking at first result 
+// and giving up after 1000.
+double FGCommList::FindClosest( double lon, double lat, double elev, ATCData& ad, atc_type tp, double max_range) {
+	int num_stations = 0;
+	int range = 10;
+	comm_list_type stations;
+	comm_list_iterator itr;
+	double distance = -9999.0;
+	
+	while(num_stations == 0) {
+		num_stations = FindByPos(lon, lat, elev, range, &stations, tp);
+		if(num_stations) {
+			double closest = max_range * SG_NM_TO_METER;
+			double tmp;
+			for(itr = stations.begin(); itr != stations.end(); ++itr) {	
+				ATCData ad2 = *itr;
+				//Point3D p1(*itr.lon, *itr.lat, *itr.elev);
+				Point3D p1(ad2.lon, ad2.lat, ad2.elev);
+				FGAirport a;
+				if(dclFindAirportID(ad2.ident, &a)) {
+					Point3D p2(lon, lat, elev);
+					tmp = dclGetHorizontalSeparation(p1, p2);
+					if(tmp <= closest) {
+						closest = tmp;
+						distance = tmp;
+						ad = *itr;
+					}
+				}
+			}
+			//cout << "Closest station is " << ad.ident << " at a range of " << distance << " meters\n";
+			return(distance);
+		}
+		if(range > max_range) {
+			break;
+		}
+		range *= 10;
+	}
+	return(-9999.0);
+}
+
+
 // Find by Airport code.
 // This is basically a wrapper for a call to the airport database to get the airport
 // position followed by a call to FindByPos(...)
diff --git a/src/ATC/commlist.hxx b/src/ATC/commlist.hxx
index 873d870be..74ee43a43 100644
--- a/src/ATC/commlist.hxx
+++ b/src/ATC/commlist.hxx
@@ -84,6 +84,17 @@ public:
 	// ** stations is erased before use **
     int FindByPos( double lon, double lat, double elev, double range, comm_list_type* stations, atc_type tp = INVALID );
 	
+	// Returns the distance in meters to the closest station of a given type,
+	// with the details written into ATCData& ad.  If no type is specifed simply
+	// returns the distance to the closest station of any type.
+	// Returns -9999 if no stations found within max_range in nautical miles (default 100 miles).
+	// Note that the search algorithm starts at 10 miles and multiplies by 10 thereafter, so if
+	// say 300 miles is specifed 10, then 100, then 1000 will be searched, breaking at first result 
+	// and giving up after 1000.
+	// !!!Be warned that searching anything over 100 miles will pause the sim unacceptably!!!
+	//	(The ability to search longer ranges should be used during init only).
+	double FindClosest( double lon, double lat, double elev, ATCData& ad, atc_type tp = INVALID, double max_range = 100.0 );
+	
 	// Find by Airport code.
 	bool FindByCode( string ICAO, ATCData& ad, atc_type tp = INVALID );