bugfix

[flightgear.git] / src / Environment / environment_ctrl.cxx

diff --git a/src/Environment/environment_ctrl.cxx b/src/Environment/environment_ctrl.cxx
index 5b9cfcfb99744b5e0a72843dbb252f57ab1518d8..0aa3572f6dca179ae109da33ddbe0ce45fc45490 100644 (file)
--- a/src/Environment/environment_ctrl.cxx
+++ b/src/Environment/environment_ctrl.cxx
@@ -34,6 +34,7 @@
 #include <Main/fg_props.hxx>
 #include <Main/util.hxx>
 
+#include "atmosphere.hxx"
 #include "fgmetar.hxx"
 #include "environment_ctrl.hxx"
 
@@ -44,6 +45,10 @@ public:
        virtual bool passAirport(FGAirport* aApt) const {
                return aApt->getMetar();
        }
+  
+  // permit heliports and seaports too
+  virtual FGPositioned::Type maxType() const
+  { return FGPositioned::SEAPORT; }
 };
 
 static AirportWithMetar airportWithMetarFilter;
@@ -433,6 +438,25 @@ static inline double convert_to_180( double d )
        return d > 180.0 ? d - 360.0 : d;
 }
 
+// Return the sea level pressure for a metar observation, in inHg.
+// This is different from QNH because it accounts for the current
+// temperature at the observation point.
+// metarPressure in inHg
+// fieldHt in ft
+// fieldTemp in C
+
+static double reducePressureSl(double metarPressure, double fieldHt,
+                               double fieldTemp)
+{
+    double elev = fieldHt * SG_FEET_TO_METER;
+    double fieldPressure
+        = FGAtmo::fieldPressure(elev, metarPressure * atmodel::inHg);
+    double slPressure = P_layer(0, elev, fieldPressure,
+                                fieldTemp + atmodel::freezing,
+                                atmodel::ISA::lam0);
+    return slPressure / atmodel::inHg;
+}
+
 void
 FGMetarCtrl::update(double dt)
 {
@@ -444,6 +468,7 @@ FGMetarCtrl::update(double dt)
 
        bool reinit_required = false;
        bool layer_rebuild_required = false;
+        double station_elevation_ft = station_elevation_n->getDoubleValue();
 
        if (first_update) {
                double dir = base_wind_dir_n->getDoubleValue()+magnetic_variation_n->getDoubleValue();
@@ -455,7 +480,10 @@ FGMetarCtrl::update(double dt)
                fgDefaultWeatherValue("visibility-m", metarvis);
 
                double metarpressure = pressure_n->getDoubleValue();
-               fgDefaultWeatherValue("pressure-sea-level-inhg", metarpressure);
+               fgDefaultWeatherValue("pressure-sea-level-inhg",
+                                      reducePressureSl(metarpressure,
+                                                       station_elevation_ft,
+                                                       temperature_n->getDoubleValue()));
 
                // We haven't already loaded a METAR, so apply it immediately.
                vector<SGPropertyNode_ptr> layers = clouds_n->getChildren("layer");
@@ -597,8 +625,11 @@ FGMetarCtrl::update(double dt)
 
                double pressure = boundary_sea_level_pressure_n->getDoubleValue();
                double metarpressure = pressure_n->getDoubleValue();
-               if( pressure != metarpressure ) {
-                       pressure = interpolate_val( pressure, metarpressure, MaxPressureChangeInHgSec );
+                double newpressure = reducePressureSl(metarpressure,
+                                                      station_elevation_ft,
+                                                      temperature_n->getDoubleValue());
+               if( pressure != newpressure ) {
+                       pressure = interpolate_val( pressure, newpressure, MaxPressureChangeInHgSec );
                        fgDefaultWeatherValue("pressure-sea-level-inhg", pressure);
                        reinit_required = true;
                }
@@ -666,11 +697,8 @@ FGMetarCtrl::update(double dt)
                        }
                }
        }
-       {
-               double station_elevation_ft = station_elevation_n->getDoubleValue();
-               set_temp_at_altitude(temperature_n->getDoubleValue(), station_elevation_ft);
-               set_dewpoint_at_altitude(dewpoint_n->getDoubleValue(), station_elevation_ft);
-       }
+        set_temp_at_altitude(temperature_n->getDoubleValue(), station_elevation_ft);
+        set_dewpoint_at_altitude(dewpoint_n->getDoubleValue(), station_elevation_ft);
        //TODO: check if temperature/dewpoint have changed. This requires reinit.
 
        // Force an update of the 3D clouds