Updates from Christian Mayer to put some of the weather data "on the bus."

src/WeatherCM/FGLocalWeatherDatabase.cpp

@@ -42,6 +42,10 @@ HISTORY
                                 Eberly's spherical interpolation code. This
 				stops our dependancy on the (ugly) voronoi
 				code and simplyfies the code structure a lot.
+07.05.2000 Tony Peden           Added functionality to get the weather data
+                                on 'the bus'
+18.05.2000 Christian Mayer      Minor clean-ups. Changed the code to use 
+                                FGWeatherUtils.h for unit conversion
 *****************************************************************************/
 
 /****************************************************************************/
@@ -49,7 +53,6 @@ HISTORY
 /****************************************************************************/
 #include <simgear/compiler.h>
 #include <simgear/constants.h>
-#include <simgear/misc/fgpath.hxx>
 
 #include <Aircraft/aircraft.hxx>
 
@@ -57,6 +60,8 @@ HISTORY
 
 #include "FGWeatherParse.h"
 
+#include "FGWeatherUtils.h"
+
 /****************************************************************************/
 /********************************** CODE ************************************/
 /****************************************************************************/
@@ -66,7 +71,7 @@ FGLocalWeatherDatabase *WeatherDatabase;
 
 void FGLocalWeatherDatabase::init( const WeatherPrecision visibility,
 				   const DatabaseWorkingType type,
-				   const string& root )
+				   const string &root )
 {
     cerr << "Initializing FGLocalWeatherDatabase\n";
     cerr << "-----------------------------------\n";
@@ -98,10 +103,7 @@ void FGLocalWeatherDatabase::init( const WeatherPrecision visibility,
 	{
 	    FGWeatherParse *parsed_data = new FGWeatherParse();
 
-	    FGPath file( root );
+	    parsed_data->input( "weather/current.gz" );
-	    file.append( "Weather" );
-	    file.append( "current.txt.gz" );
-	    parsed_data->input( file.c_str() );
 	    unsigned int n = parsed_data->stored_stations();
 
 	    sgVec2               *p = new sgVec2              [n];
@@ -251,33 +253,29 @@ void FGLocalWeatherDatabase::setProperties(const FGPhysicalProperties2D& x)
 void fgUpdateWeatherDatabase(void)
 {
     sgVec3 position;
-	sgVec3 wind;
+    sgVec3 wind;
     
     
-	sgSetVec3(position, 
+    sgSetVec3(position, 
-	current_aircraft.fdm_state->get_Latitude(),
+        current_aircraft.fdm_state->get_Latitude(),
-	current_aircraft.fdm_state->get_Longitude(),
+        current_aircraft.fdm_state->get_Longitude(),
-	current_aircraft.fdm_state->get_Altitude() * FEET_TO_METER);
+        current_aircraft.fdm_state->get_Altitude() * FEET_TO_METER);
     
     WeatherDatabase->update( position );
        
-	#define rho0 1.293 /*for air in normal altitudes*/
+    // get the data on 'the bus' for the FDM
-    #define PATOPSF  0.02089    // Pascals to psf
-	#define KTOR     1.8        // Kelvin to degree Rankine
-	#define KGMTOSGF 0.0019403  // kg/m^3 to slug/ft^3
 
+    FGPhysicalProperty porperty = WeatherDatabase->get(position);
 
-    FGPhysicalProperty my_value = WeatherDatabase->get(position);
+    current_aircraft.fdm_state->set_Static_temperature( Kelvin2Rankine(porperty.Temperature) );
-    current_aircraft.fdm_state->set_Static_temperature(my_value.Temperature*KTOR);
+    current_aircraft.fdm_state->set_Static_pressure( Pascal2psf(porperty.AirPressure) );
-    current_aircraft.fdm_state->set_Static_pressure(my_value.AirPressure*PATOPSF);
+
-    float density=rho0 * 273.15 * my_value.AirPressure / (101300 *my_value.Temperature )*KGMTOSGF;
+    current_aircraft.fdm_state->set_Density( SIdensity2JSBsim( Density(porperty.AirPressure, porperty.Temperature) ) );
-    current_aircraft.fdm_state->set_Density(density*KGMTOSGF);
     
-#define KPHTOFPS 0.9113 //km/hr to ft/s
 #define MSTOFPS  3.2808 //m/s to ft/s
-    current_aircraft.fdm_state->set_Velocities_Local_Airmass(my_value.Wind[1]*KPHTOFPS,
+    current_aircraft.fdm_state->set_Velocities_Local_Airmass(porperty.Wind[1]*MSTOFPS,
-							     my_value.Wind[0]*KPHTOFPS,
+        porperty.Wind[0]*MSTOFPS,
-							     my_value.Wind[2]*KPHTOFPS);
+        porperty.Wind[2]*MSTOFPS);
     
 }
 

src/WeatherCM/FGLocalWeatherDatabase.h

@@ -114,7 +114,7 @@ public:
 
     void init( const WeatherPrecision visibility,
 	       const DatabaseWorkingType type,
-	       const string& root );
+	       const string &root );
 
     /************************************************************************/
     /* Constructor and Destructor					    */

src/WeatherCM/FGWeatherUtils.h

@@ -39,6 +39,8 @@ HISTORY
 				and lots of wee code cleaning
 17.01.2000 Christian Mayer	Added conversion routines make it easier for
 				JSBsim to use the weather database.
+18.05.2000 Christian Mayer      Added function for geting the density when
+                                temperature and pressure are given
 *****************************************************************************/
 
 /****************************************************************************/
@@ -71,7 +73,7 @@ HISTORY
 /* dp:	    dew point in °C						    */
 /* wb:	    approximate wetbulp in °C					    */
 /*									    */
-/* NOTE: Pascal is the SI unit for preasure and is defined as Pa = N/m^2    */
+/* NOTE: Pascal is the SI unit for pressure and is defined as Pa = N/m^2    */
 /*       1 mbar = 1 hPa = 100 Pa					    */
 /* NOTE: °C isn't a SI unit, so I should use °K instead. But as all	    */
 /*       formulas are given in °C and the weather database only uses	    */
@@ -141,24 +143,32 @@ inline WeatherPrecision wb(const WeatherPrecision t, const WeatherPrecision p, c
 
 }
 
+// Assume that we've got an ideal gas in normal altitudes
+inline WeatherPrecision Density(const WeatherPrecision AirPressure, const WeatherPrecision Temperature )
+{
+    const float rho0 = 1.293; /*density for air in normal altitudes at 0°C and 1013 mbar*/
+
+    return rho0 * 273.15 * AirPressure / (101300.0 * Temperature);
+}
+
 inline WeatherPrecision Celsius		    (const WeatherPrecision celsius)
 {
-    return celsius + 273.16;				//Kelvin
+    return celsius + 273.15;				//Kelvin
 }
 
 inline WeatherPrecision Fahrenheit	    (const WeatherPrecision fahrenheit)
 {
-    return (fahrenheit * 9.0 / 5.0) + 32.0 + 273.16;	//Kelvin
+    return (fahrenheit * 9.0 / 5.0) + 32.0 + 273.15;	//Kelvin
 }
 
 inline WeatherPrecision Kelvin2Celsius	    (const WeatherPrecision kelvin)
 {
-    return kelvin - 273.16;				//Celsius
+    return kelvin - 273.15;				//Celsius
 }
 
 inline WeatherPrecision Kelvin2Fahrenheit   (const WeatherPrecision kelvin)
 {
-    return ((kelvin - 273.16) * 9.0 / 5.0) + 32.0;	//Fahrenheit
+    return ((kelvin - 273.15) * 9.0 / 5.0) + 32.0;	//Fahrenheit
 }
 
 inline WeatherPrecision Celsius2Fahrenheit  (const WeatherPrecision celsius)