src/Environment/metarproperties.cxx

   1 // metarproperties.cxx -- Parse a METAR and write properties
   2 //
   3 // Written by David Megginson, started May 2002.
   4 // Rewritten by Torsten Dreyer, August 2010
   5 //
   6 // Copyright (C) 2002  David Megginson - david@megginson.com
   7 //
   8 // This program is free software; you can redistribute it and/or
   9 // modify it under the terms of the GNU General Public License as
  10 // published by the Free Software Foundation; either version 2 of the
  11 // License, or (at your option) any later version.
  12 //
  13 // This program is distributed in the hope that it will be useful, but
  14 // WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 // General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  21 //
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include <config.h>
  25 #endif
  26
  27 #include "metarproperties.hxx"
  28 #include "fgmetar.hxx"
  29 #include "environment.hxx"
  30 #include "atmosphere.hxx"
  31 #include <simgear/scene/sky/cloud.hxx>
  32 #include <simgear/structure/exception.hxx>
  33 #include <Main/fg_props.hxx>
  34
  35 using std::string;
  36
  37 namespace Environment {
  38
  39 static vector<string> coverage_string;
  40
  41 MetarProperties::MetarProperties( SGPropertyNode_ptr rootNode ) :
  42   _rootNode(rootNode),
  43   _metarValidNode( rootNode->getNode( "valid", true ) ),
  44   _station_elevation(0.0),
  45   _station_latitude(0.0),
  46   _station_longitude(0.0),
  47   _min_visibility(16000.0),
  48   _max_visibility(16000.0),
  49   _base_wind_dir(0),
  50   _base_wind_range_from(0),
  51   _base_wind_range_to(0),
  52   _wind_speed(0.0),
  53   _wind_from_north_fps(0.0),
  54   _wind_from_east_fps(0.0),
  55   _gusts(0.0),
  56   _temperature(0.0),
  57   _dewpoint(0.0),
  58   _humidity(0.0),
  59   _pressure(0.0),
  60   _sea_level_temperature(0.0),
  61   _sea_level_dewpoint(0.0),
  62   _sea_level_pressure(29.92),
  63   _rain(0.0),
  64   _hail(0.0),
  65   _snow(0.0),
  66   _snow_cover(false)
  67 {
  68   // Hack to avoid static initialization order problems on OSX
  69   if( coverage_string.size() == 0 ) {
  70     coverage_string.push_back(SGCloudLayer::SG_CLOUD_CLEAR_STRING);
  71     coverage_string.push_back(SGCloudLayer::SG_CLOUD_FEW_STRING);
  72     coverage_string.push_back(SGCloudLayer::SG_CLOUD_SCATTERED_STRING);
  73     coverage_string.push_back(SGCloudLayer::SG_CLOUD_BROKEN_STRING);
  74     coverage_string.push_back(SGCloudLayer::SG_CLOUD_OVERCAST_STRING);
  75   }
  76   // don't tie metar-valid, so listeners get triggered
  77   _metarValidNode->setBoolValue( false );
  78   _tiedProperties.setRoot( _rootNode );
  79   _tiedProperties.Tie("data", this, &MetarProperties::get_metar, &MetarProperties::set_metar );
  80   _tiedProperties.Tie("station-id", this, &MetarProperties::get_station_id );
  81   _tiedProperties.Tie("station-elevation-ft", &_station_elevation );
  82   _tiedProperties.Tie("station-latitude-deg", &_station_latitude );
  83   _tiedProperties.Tie("station-longitude-deg", &_station_longitude );
  84   _tiedProperties.Tie("min-visibility-m", &_min_visibility );
  85   _tiedProperties.Tie("max-visibility-m", &_max_visibility );
  86   _tiedProperties.Tie("base-wind-range-from", &_base_wind_range_from );
  87   _tiedProperties.Tie("base-wind-range-to", &_base_wind_range_to );
  88   _tiedProperties.Tie("base-wind-speed-kt", &_wind_speed );
  89   _tiedProperties.Tie("base-wind-dir-deg", &_base_wind_dir );
  90   _tiedProperties.Tie("base-wind-from-north-fps", &_wind_from_north_fps );
  91   _tiedProperties.Tie("base-wind-from-east-fps", &_wind_from_east_fps );
  92   _tiedProperties.Tie("gust-wind-speed-kt", &_gusts );
  93   _tiedProperties.Tie("temperature-degc", &_temperature );
  94   _tiedProperties.Tie("dewpoint-degc", &_dewpoint );
  95   _tiedProperties.Tie("rel-humidity-norm", &_humidity );
  96   _tiedProperties.Tie("pressure-inhg", &_pressure );
  97   _tiedProperties.Tie("temperature-sea-level-degc", &_sea_level_temperature );
  98   _tiedProperties.Tie("dewpoint-sea-level-degc", &_sea_level_dewpoint );
  99   _tiedProperties.Tie("pressure-sea-level-inhg", &_sea_level_pressure );
 100   _tiedProperties.Tie("rain-norm", &_rain );
 101   _tiedProperties.Tie("hail-norm", &_hail );
 102   _tiedProperties.Tie("snow-norm", &_snow);
 103   _tiedProperties.Tie("snow-cover", &_snow_cover );
 104   _tiedProperties.Tie("decoded", this, &MetarProperties::get_decoded );
 105 }
 106
 107 MetarProperties::~MetarProperties()
 108 {
 109 }
 110
 111
 112 static const double thickness_value[] = { 0, 65, 600, 750, 1000 };
 113
 114 void MetarProperties::set_metar( const char * metar )
 115 {
 116     _metar = metar;
 117
 118     SGSharedPtr<FGMetar> m;
 119     try {
 120         m = new FGMetar( _metar );
 121     }
 122     catch( sg_io_exception ) {
 123         SG_LOG( SG_GENERAL, SG_WARN, "Can't parse metar: " << _metar );
 124         _metarValidNode->setBoolValue(false);
 125         return;
 126     }
 127
 128     _decoded.clear();
 129     const vector<string> weather = m->getWeather();
 130     for( vector<string>::const_iterator it = weather.begin(); it != weather.end(); it++ ) {
 131         if( false == _decoded.empty() ) _decoded.append(", ");
 132         _decoded.append(*it);
 133     }
 134
 135     _min_visibility = m->getMinVisibility().getVisibility_m();
 136     _max_visibility = m->getMaxVisibility().getVisibility_m();
 137
 138     const SGMetarVisibility *dirvis = m->getDirVisibility();
 139     for ( int i = 0; i < 8; i++, dirvis++) {
 140         SGPropertyNode *vis = _rootNode->getChild("visibility", i, true);
 141         double v = dirvis->getVisibility_m();
 142
 143         vis->setDoubleValue("min-m", v);
 144         vis->setDoubleValue("max-m", v);
 145     }
 146
 147     _base_wind_dir = m->getWindDir();
 148     _base_wind_range_from = m->getWindRangeFrom();
 149     _base_wind_range_to = m->getWindRangeTo();
 150     _wind_speed = m->getWindSpeed_kt();
 151
 152     double speed_fps = _wind_speed * SG_NM_TO_METER * SG_METER_TO_FEET / 3600.0;
 153     _wind_from_north_fps = speed_fps * cos((double)_base_wind_dir * SGD_DEGREES_TO_RADIANS);
 154     _wind_from_east_fps = speed_fps * sin((double)_base_wind_dir * SGD_DEGREES_TO_RADIANS);
 155     _gusts = m->getGustSpeed_kt();
 156     _temperature = m->getTemperature_C();
 157     _dewpoint = m->getDewpoint_C();
 158     _humidity = m->getRelHumidity();
 159     _pressure = m->getPressure_inHg();
 160
 161     {
 162         // 1. check the id given in the metar
 163         FGAirport* a = FGAirport::findByIdent(m->getId());
 164 /*
 165         // 2. if unknown, find closest airport with metar to current position
 166         if( a == NULL ) {
 167             SGGeod pos = SGGeod::fromDeg(_longitude_n->getDoubleValue(), _latitude_n->getDoubleValue());
 168             a = FGAirport::findClosest(pos, 10000.0, &_airportWithMetarFilter);
 169         }
 170 */
 171         // 3. otherwise use ground elevation
 172         if( a != NULL ) {
 173             _station_elevation = a->getElevation();
 174             const SGGeod & towerPosition = a->getTowerLocation();
 175             _station_latitude = towerPosition.getLatitudeDeg();
 176             _station_longitude = towerPosition.getLongitudeDeg();
 177             _station_id = a->ident();
 178         } else {
 179             _station_elevation = 0.0;
 180             _station_latitude = 0.0;
 181             _station_longitude = 0.0;
 182             _station_id = "XXXX";
 183 //            station_elevation_ft = _ground_elevation_n->getDoubleValue() * SG_METER_TO_FEET;
 184 //            _station_id = m->getId();
 185         }
 186     }
 187
 188     {    // calculate sea level temperature, dewpoint and pressure
 189         FGEnvironment dummy; // instantiate a dummy so we can leech a method
 190         dummy.set_elevation_ft( _station_elevation );
 191         dummy.set_temperature_degc( _temperature );
 192         dummy.set_dewpoint_degc( _dewpoint );
 193         _sea_level_temperature = dummy.get_temperature_sea_level_degc();
 194         _sea_level_dewpoint = dummy.get_dewpoint_sea_level_degc();
 195
 196         double elevation_m = _station_elevation * SG_FEET_TO_METER;
 197         double fieldPressure = FGAtmo::fieldPressure( elevation_m, _pressure * atmodel::inHg );
 198         _sea_level_pressure = P_layer(0, elevation_m, fieldPressure, _temperature + atmodel::freezing, atmodel::ISA::lam0) / atmodel::inHg;
 199     }
 200
 201     bool isBC = false;
 202     bool isBR = false;
 203     bool isFG = false;
 204     bool isMI = false;
 205     bool isHZ = false;
 206
 207     {
 208         for( unsigned i = 0; i < 3; i++ ) {
 209             SGPropertyNode_ptr n = _rootNode->getChild("weather", i, true );
 210             vector<struct SGMetar::Weather> weather = m->getWeather2();
 211             struct SGMetar::Weather * w = i < weather.size() ? &weather[i] : NULL;
 212             n->getNode("intensity",true)->setIntValue( w != NULL ? w->intensity : 0 );
 213             n->getNode("vincinity",true)->setBoolValue( w != NULL ? w->vincinity : false );
 214             for( unsigned j = 0; j < 3; j++ ) {
 215
 216                 const string & phenomenon = w != NULL && j < w->phenomena.size() ? w->phenomena[j].c_str() : "";
 217                 n->getChild( "phenomenon", j, true )->setStringValue( phenomenon );
 218
 219                 const string & description = w != NULL && j < w->descriptions.size() ? w->descriptions[j].c_str() : "";
 220                 n->getChild( "description", j, true )->setStringValue( description );
 221
 222                 // need to know later,
 223                 // if its fog(FG) (might be shallow(MI) or patches(BC)) or haze (HZ) or mist(BR)
 224                 if( phenomenon == "FG" ) isFG = true;
 225                 if( phenomenon == "HZ" ) isHZ = true;
 226                 if( phenomenon == "BR" ) isBR = true;
 227                 if( description == "MI" ) isMI = true;
 228                 if( description == "BC" ) isBC = true;
 229             }
 230         }
 231     }
 232
 233     vector<SGMetarCloud> cv = m->getClouds();
 234     vector<SGMetarCloud>::const_iterator cloud, cloud_end = cv.end();
 235
 236     {
 237         static const char * LAYER = "layer";
 238         SGPropertyNode_ptr cloudsNode = _rootNode->getNode("clouds", true );
 239         const vector<SGMetarCloud> & metarClouds = m->getClouds();
 240         unsigned layerOffset = 0; // Oh, this is ugly!
 241         bool setGroundCloudLayer = _rootNode->getBoolValue("set-ground-cloud-layer", false );
 242         if( setGroundCloudLayer ) {
 243             // create a cloud layer #0 starting at the ground if its fog, mist or haze
 244
 245             // make sure layer actually starts at ground and set it's bottom at a constant
 246             // value below the station's elevation
 247             const double LAYER_BOTTOM_BELOW_STATION_ELEVATION =
 248               fgGetDouble( "/environment/config/offset-from-station-elevation-ft", 200 );
 249
 250             SGMetarCloud::Coverage coverage = SGMetarCloud::COVERAGE_NIL;
 251             double thickness = 0;
 252             double alpha = 1.0;
 253
 254             if( isFG ) { // fog
 255                 coverage = SGMetarCloud::getCoverage( isBC ?
 256                     fgGetString( "/environment/config/fog-bc-2dlayer-coverage", SGMetarCloud::COVERAGE_SCATTERED_STRING ) :
 257                     fgGetString( "/environment/config/fog-2dlayer-coverage", SGMetarCloud::COVERAGE_BROKEN_STRING )
 258                 );
 259
 260                 thickness = isMI ?
 261                    fgGetDouble("/environment/config/fog-shallow-thickness-ft",30) + LAYER_BOTTOM_BELOW_STATION_ELEVATION : // shallow fog, 10m/30ft
 262                    fgGetDouble("/environment/config/fog-thickness-ft",500) + LAYER_BOTTOM_BELOW_STATION_ELEVATION; // fog, 150m/500ft
 263                 alpha =  fgGetDouble("/environment/config/fog-alpha",0.0);
 264             } else if( isBR ) { // mist
 265                 coverage = SGMetarCloud::getCoverage(fgGetString("/environment/config/mist-2dlayer-coverage", SGMetarCloud::COVERAGE_OVERCAST_STRING));
 266                 thickness =  fgGetDouble("/environment/config/mist-thickness-ft",2000) + LAYER_BOTTOM_BELOW_STATION_ELEVATION;
 267                 alpha =  fgGetDouble("/environment/config/mist-alpha",0.8);
 268             } else if( isHZ ) { // hase
 269                 coverage = SGMetarCloud::getCoverage(fgGetString("/environment/config/mist-2dlayer-coverage", SGMetarCloud::COVERAGE_OVERCAST_STRING));
 270                 thickness =  fgGetDouble("/environment/config/haze-thickness-ft",2000) + LAYER_BOTTOM_BELOW_STATION_ELEVATION;
 271                 alpha =  fgGetDouble("/environment/config/haze-alpha",0.6);
 272             }
 273
 274             if( coverage != SGMetarCloud::COVERAGE_NIL ) {
 275                 SGPropertyNode_ptr layerNode = cloudsNode->getChild(LAYER, 0, true );
 276                 layerNode->setDoubleValue( "coverage-type", SGCloudLayer::getCoverageType(coverage_string[coverage]) );
 277                 layerNode->setStringValue( "coverage", coverage_string[coverage] );
 278                 layerNode->setDoubleValue( "elevation-ft", _station_elevation - LAYER_BOTTOM_BELOW_STATION_ELEVATION );
 279                 layerNode->setDoubleValue( "thickness-ft", thickness );
 280                 layerNode->setDoubleValue( "visibility-m", _min_visibility );
 281                 layerNode->setDoubleValue( "alpha", alpha );
 282                 _min_visibility = _max_visibility =
 283                   fgGetDouble("/environment/config/visibility-above-layer-m",20000.0); // assume good visibility above the fog
 284                 layerOffset = 1;  // shudder
 285             }
 286         }
 287
 288         for( unsigned i = 0; i < 5-layerOffset; i++ ) {
 289             SGPropertyNode_ptr layerNode = cloudsNode->getChild(LAYER, i+layerOffset, true );
 290             SGMetarCloud::Coverage coverage = i < metarClouds.size() ? metarClouds[i].getCoverage() : SGMetarCloud::COVERAGE_CLEAR;
 291             double elevation =
 292                 i >= metarClouds.size() || coverage == SGMetarCloud::COVERAGE_CLEAR ?
 293                 -9999.0 :
 294                 metarClouds[i].getAltitude_ft() + _station_elevation;
 295
 296             layerNode->setStringValue( "coverage", coverage_string[coverage] );
 297             layerNode->setDoubleValue( "coverage-type", SGCloudLayer::getCoverageType(coverage_string[coverage]) );
 298             layerNode->setDoubleValue( "elevation-ft", elevation );
 299             layerNode->setDoubleValue( "thickness-ft", thickness_value[coverage]);
 300             layerNode->setDoubleValue( "span-m", 40000 );
 301             layerNode->setDoubleValue( "visibility-m", 50.0 );
 302         }
 303     }
 304
 305     _rain = m->getRain();
 306     _hail = m->getHail();
 307     _snow = m->getSnow();
 308     _snow_cover = m->getSnowCover();
 309     _metarValidNode->setBoolValue(true);
 310 }
 311
 312 } // namespace Environment