1 // metarproperties.cxx -- Parse a METAR and write properties
3 // Written by David Megginson, started May 2002.
4 // Rewritten by Torsten Dreyer, August 2010
6 // Copyright (C) 2002 David Megginson - david@megginson.com
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.
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.
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.
27 #include <cstring> // for strlen
29 #include "metarproperties.hxx"
30 #include "fgmetar.hxx"
31 #include "environment.hxx"
32 #include "atmosphere.hxx"
33 #include "metarairportfilter.hxx"
34 #include <simgear/scene/sky/cloud.hxx>
35 #include <simgear/structure/exception.hxx>
36 #include <simgear/misc/strutils.hxx>
37 #include <simgear/magvar/magvar.hxx>
38 #include <simgear/timing/sg_time.hxx>
39 #include <Main/fg_props.hxx>
43 namespace Environment {
45 static vector<string> coverage_string;
48 * @brief Helper class to wrap SGMagVar functionality and cache the variation and dip for
51 class MagneticVariation : public SGMagVar {
56 MagneticVariation() : _lat(1), _lon(1), _alt(1) {
57 recalc( 0.0, 0.0, 0.0 );
61 * @brief get the magnetic variation for a specific position at the current time
62 * @param lon the positions longitude in degrees
63 * @param lat the positions latitude in degrees
64 * @param alt the positions height above MSL (aka altitude) in feet
65 * @return the magnetic variation in degrees
67 double get_variation_deg( double lon, double lat, double alt );
70 * @brief get the magnetic dip for a specific position at the current time
71 * @param lon the positions longitude in degrees
72 * @param lat the positions latitude in degrees
73 * @param alt the positions height above MSL (aka altitude) in feet
74 * @return the magnetic dip in degrees
76 double get_dip_deg( double lon, double lat, double alt );
78 void recalc( double lon, double lat, double alt );
80 double _lat, _lon, _alt;
83 inline void MagneticVariation::recalc( double lon, double lat, double alt )
85 // calculation of magnetic variation is expensive. Cache the position
86 // and perform this calculation only if it has changed
87 if( _lon != lon || _lat != lat || _alt != alt ) {
88 SG_LOG(SG_ENVIRONMENT, SG_DEBUG, "Recalculating magvar for lon=" << lon << ", lat=" << lat << ", alt=" << alt );
93 SGGeod location(SGGeod::fromDegFt(lon, lat, alt));
94 _time.update( location, 0, 0 );
95 update( lon, lat, alt, _time.getJD() );
99 inline double MagneticVariation::get_variation_deg( double lon, double lat, double alt )
101 recalc( lon, lat, alt );
102 return get_magvar() * SGD_RADIANS_TO_DEGREES;
105 inline double MagneticVariation::get_dip_deg( double lon, double lat, double alt )
107 recalc( lon, lat, alt );
108 return get_magdip() * SGD_RADIANS_TO_DEGREES;
111 MetarProperties::MetarProperties( SGPropertyNode_ptr rootNode ) :
113 _metarValidNode( rootNode->getNode( "valid", true ) ),
114 _station_elevation(0.0),
115 _station_latitude(0.0),
116 _station_longitude(0.0),
117 _min_visibility(16000.0),
118 _max_visibility(16000.0),
120 _base_wind_range_from(0),
121 _base_wind_range_to(0),
123 _wind_from_north_fps(0.0),
124 _wind_from_east_fps(0.0),
130 _sea_level_temperature(0.0),
131 _sea_level_dewpoint(0.0),
132 _sea_level_pressure(29.92),
137 _magneticVariation(new MagneticVariation())
139 // Hack to avoid static initialization order problems on OSX
140 if( coverage_string.empty() ) {
141 coverage_string.push_back(SGCloudLayer::SG_CLOUD_CLEAR_STRING);
142 coverage_string.push_back(SGCloudLayer::SG_CLOUD_FEW_STRING);
143 coverage_string.push_back(SGCloudLayer::SG_CLOUD_SCATTERED_STRING);
144 coverage_string.push_back(SGCloudLayer::SG_CLOUD_BROKEN_STRING);
145 coverage_string.push_back(SGCloudLayer::SG_CLOUD_OVERCAST_STRING);
147 // don't tie metar-valid, so listeners get triggered
148 _metarValidNode->setBoolValue( false );
149 _tiedProperties.setRoot( _rootNode );
150 _tiedProperties.Tie("data", this, &MetarProperties::get_metar, &MetarProperties::set_metar );
151 _tiedProperties.Tie("station-id", this, &MetarProperties::get_station_id, &MetarProperties::set_station_id );
152 _tiedProperties.Tie("station-elevation-ft", &_station_elevation );
153 _tiedProperties.Tie("station-latitude-deg", &_station_latitude );
154 _tiedProperties.Tie("station-longitude-deg", &_station_longitude );
155 _tiedProperties.Tie("station-magnetic-variation-deg", this, &MetarProperties::get_magnetic_variation_deg );
156 _tiedProperties.Tie("station-magnetic-dip-deg", this, &MetarProperties::get_magnetic_dip_deg );
157 _tiedProperties.Tie("min-visibility-m", &_min_visibility );
158 _tiedProperties.Tie("max-visibility-m", &_max_visibility );
159 _tiedProperties.Tie("base-wind-range-from", &_base_wind_range_from );
160 _tiedProperties.Tie("base-wind-range-to", &_base_wind_range_to );
161 _tiedProperties.Tie("base-wind-speed-kt", this, &MetarProperties::get_wind_speed, &MetarProperties::set_wind_speed );
162 _tiedProperties.Tie("base-wind-dir-deg", this, &MetarProperties::get_base_wind_dir, &MetarProperties::set_base_wind_dir );
163 _tiedProperties.Tie("base-wind-from-north-fps", this, &MetarProperties::get_wind_from_north_fps, &MetarProperties::set_wind_from_north_fps );
164 _tiedProperties.Tie("base-wind-from-east-fps",this, &MetarProperties::get_wind_from_east_fps, &MetarProperties::set_wind_from_east_fps );
165 _tiedProperties.Tie("gust-wind-speed-kt", &_gusts );
166 _tiedProperties.Tie("temperature-degc", &_temperature );
167 _tiedProperties.Tie("dewpoint-degc", &_dewpoint );
168 _tiedProperties.Tie("rel-humidity-norm", &_humidity );
169 _tiedProperties.Tie("pressure-inhg", &_pressure );
170 _tiedProperties.Tie("temperature-sea-level-degc", &_sea_level_temperature );
171 _tiedProperties.Tie("dewpoint-sea-level-degc", &_sea_level_dewpoint );
172 _tiedProperties.Tie("pressure-sea-level-inhg", &_sea_level_pressure );
173 _tiedProperties.Tie("rain-norm", &_rain );
174 _tiedProperties.Tie("hail-norm", &_hail );
175 _tiedProperties.Tie("snow-norm", &_snow);
176 _tiedProperties.Tie("snow-cover", &_snow_cover );
177 _tiedProperties.Tie("decoded", this, &MetarProperties::get_decoded );
180 MetarProperties::~MetarProperties()
182 delete _magneticVariation;
186 static const double thickness_value[] = { 0, 65, 600, 750, 1000 };
188 const char* MetarProperties::get_metar() const
190 if (!_metar) return "";
191 return _metar->getData();
194 void MetarProperties::set_metar( const char * metarString )
196 SGSharedPtr<FGMetar> m;
197 if ((metarString == NULL) || (strlen(metarString) == 0)) {
203 m = new FGMetar( metarString );
205 catch( sg_io_exception ) {
206 SG_LOG( SG_ENVIRONMENT, SG_WARN, "Can't parse metar: " << metarString );
207 _metarValidNode->setBoolValue(false);
214 void MetarProperties::setMetar( SGSharedPtr<FGMetar> m )
222 const vector<string> weather = m->getWeather();
223 for( vector<string>::const_iterator it = weather.begin(); it != weather.end(); ++it ) {
224 if( false == _decoded.empty() ) _decoded.append(", ");
225 _decoded.append(*it);
228 _min_visibility = m->getMinVisibility().getVisibility_m();
229 _max_visibility = m->getMaxVisibility().getVisibility_m();
231 const SGMetarVisibility *dirvis = m->getDirVisibility();
232 for ( int i = 0; i < 8; i++, dirvis++) {
233 SGPropertyNode *vis = _rootNode->getChild("visibility", i, true);
234 double v = dirvis->getVisibility_m();
236 vis->setDoubleValue("min-m", v);
237 vis->setDoubleValue("max-m", v);
240 set_base_wind_dir(m->getWindDir());
241 _base_wind_range_from = m->getWindRangeFrom();
242 _base_wind_range_to = m->getWindRangeTo();
243 set_wind_speed(m->getWindSpeed_kt());
245 _gusts = m->getGustSpeed_kt();
246 _temperature = m->getTemperature_C();
247 _dewpoint = m->getDewpoint_C();
248 _humidity = m->getRelHumidity();
249 _pressure = m->getPressure_inHg();
252 // 1. check the id given in the metar
253 FGAirport* a = FGAirport::findByIdent(m->getId());
255 // 2. if unknown, find closest airport with metar to current position
257 SGGeod pos = SGGeod::fromDeg(
258 fgGetDouble( "/position/longitude-deg", 0.0 ),
259 fgGetDouble( "/position/latitude-deg", 0.0 ) );
260 a = FGAirport::findClosest(pos, 10000.0, MetarAirportFilter::instance() );
263 // 3. otherwise use ground elevation
265 _station_elevation = a->getElevation();
266 const SGGeod & towerPosition = a->getTowerLocation();
267 _station_latitude = towerPosition.getLatitudeDeg();
268 _station_longitude = towerPosition.getLongitudeDeg();
269 _station_id = a->ident();
271 _station_elevation = fgGetDouble("/position/ground-elev-m", 0.0 ) * SG_METER_TO_FEET;
272 _station_latitude = fgGetDouble( "/position/latitude-deg", 0.0 );
273 _station_longitude = fgGetDouble( "/position/longitude-deg", 0.0 );
274 _station_id = "XXXX";
278 { // calculate sea level temperature, dewpoint and pressure
279 FGEnvironment dummy; // instantiate a dummy so we can leech a method
280 dummy.set_elevation_ft( _station_elevation );
281 dummy.set_temperature_degc( _temperature );
282 dummy.set_dewpoint_degc( _dewpoint );
283 _sea_level_temperature = dummy.get_temperature_sea_level_degc();
284 _sea_level_dewpoint = dummy.get_dewpoint_sea_level_degc();
286 double elevation_m = _station_elevation * SG_FEET_TO_METER;
287 double fieldPressure = FGAtmo::fieldPressure( elevation_m, _pressure * atmodel::inHg );
288 _sea_level_pressure = P_layer(0, elevation_m, fieldPressure, _temperature + atmodel::freezing, atmodel::ISA::lam0) / atmodel::inHg;
298 for( unsigned i = 0; i < 3; i++ ) {
299 SGPropertyNode_ptr n = _rootNode->getChild("weather", i, true );
300 vector<struct SGMetar::Weather> weather = m->getWeather2();
301 struct SGMetar::Weather * w = i < weather.size() ? &weather[i] : NULL;
302 n->getNode("intensity",true)->setIntValue( w != NULL ? w->intensity : 0 );
303 n->getNode("vincinity",true)->setBoolValue( w != NULL ? w->vincinity : false );
304 for( unsigned j = 0; j < 3; j++ ) {
306 const string & phenomenon = w != NULL && j < w->phenomena.size() ? w->phenomena[j].c_str() : "";
307 n->getChild( "phenomenon", j, true )->setStringValue( phenomenon );
309 const string & description = w != NULL && j < w->descriptions.size() ? w->descriptions[j].c_str() : "";
310 n->getChild( "description", j, true )->setStringValue( description );
312 // need to know later,
313 // if its fog(FG) (might be shallow(MI) or patches(BC)) or haze (HZ) or mist(BR)
314 if( phenomenon == "FG" ) isFG = true;
315 if( phenomenon == "HZ" ) isHZ = true;
316 if( phenomenon == "BR" ) isBR = true;
317 if( description == "MI" ) isMI = true;
318 if( description == "BC" ) isBC = true;
324 static const char * LAYER = "layer";
325 SGPropertyNode_ptr cloudsNode = _rootNode->getNode("clouds", true );
326 const vector<SGMetarCloud> & metarClouds = m->getClouds();
327 unsigned layerOffset = 0; // Oh, this is ugly!
329 // fog/mist/haze cloud layer does not work with 3d clouds yet :-(
330 bool setGroundCloudLayer = _rootNode->getBoolValue("set-ground-cloud-layer", false ) &&
331 false == (fgGetBool("/sim/rendering/shader-effects", false ) &&
332 fgGetBool("/sim/rendering/clouds3d-enable", false ) );
334 if( setGroundCloudLayer ) {
335 // create a cloud layer #0 starting at the ground if its fog, mist or haze
337 // make sure layer actually starts at ground and set it's bottom at a constant
338 // value below the station's elevation
339 const double LAYER_BOTTOM_STATION_OFFSET =
340 fgGetDouble( "/environment/params/fog-mist-haze-layer/offset-from-station-elevation-ft", -200 );
342 SGMetarCloud::Coverage coverage = SGMetarCloud::COVERAGE_NIL;
343 double thickness = 0;
347 coverage = SGMetarCloud::getCoverage( isBC ?
348 fgGetString( "/environment/params/fog-mist-haze-layer/fog-bc-2dlayer-coverage", SGMetarCloud::COVERAGE_SCATTERED_STRING ) :
349 fgGetString( "/environment/params/fog-mist-haze-layer/fog-2dlayer-coverage", SGMetarCloud::COVERAGE_BROKEN_STRING )
353 fgGetDouble("/environment/params/fog-mist-haze-layer/fog-shallow-thickness-ft",30) - LAYER_BOTTOM_STATION_OFFSET : // shallow fog, 10m/30ft
354 fgGetDouble("/environment/params/fog-mist-haze-layer/fog-thickness-ft",500) - LAYER_BOTTOM_STATION_OFFSET; // fog, 150m/500ft
355 alpha = fgGetDouble("/environment/params/fog-mist-haze-layer/fog-2dlayer-alpha", 1.0);
356 } else if( isBR ) { // mist
357 coverage = SGMetarCloud::getCoverage(fgGetString("/environment/params/fog-mist-haze-layer/mist-2dlayer-coverage", SGMetarCloud::COVERAGE_OVERCAST_STRING));
358 thickness = fgGetDouble("/environment/params/fog-mist-haze-layer/mist-thickness-ft",2000) - LAYER_BOTTOM_STATION_OFFSET;
359 alpha = fgGetDouble("/environment/params/fog-mist-haze-layer/mist-2dlayer-alpha",0.8);
360 } else if( isHZ ) { // haze
361 coverage = SGMetarCloud::getCoverage(fgGetString("/environment/params/fog-mist-haze-layer/mist-2dlayer-coverage", SGMetarCloud::COVERAGE_OVERCAST_STRING));
362 thickness = fgGetDouble("/environment/params/fog-mist-haze-layer/haze-thickness-ft",2000) - LAYER_BOTTOM_STATION_OFFSET;
363 alpha = fgGetDouble("/environment/params/fog-mist-haze-layer/haze-2dlayer-alpha",0.6);
366 if( coverage != SGMetarCloud::COVERAGE_NIL ) {
368 // if there is a layer above the fog, limit the top to one foot below that layer's bottom
369 if( metarClouds.size() > 0 && metarClouds[0].getCoverage() != SGMetarCloud::COVERAGE_CLEAR )
370 thickness = metarClouds[0].getAltitude_ft() - LAYER_BOTTOM_STATION_OFFSET - 1;
372 SGPropertyNode_ptr layerNode = cloudsNode->getChild(LAYER, 0, true );
373 layerNode->setDoubleValue( "coverage-type", SGCloudLayer::getCoverageType(coverage_string[coverage]) );
374 layerNode->setStringValue( "coverage", coverage_string[coverage] );
375 layerNode->setDoubleValue( "elevation-ft", _station_elevation + LAYER_BOTTOM_STATION_OFFSET );
376 layerNode->setDoubleValue( "thickness-ft", thickness );
377 layerNode->setDoubleValue( "visibility-m", _min_visibility );
378 layerNode->setDoubleValue( "alpha", alpha );
379 _min_visibility = _max_visibility =
380 fgGetDouble("/environment/params/fog-mist-haze-layer/visibility-above-layer-m",20000.0); // assume good visibility above the fog
381 layerOffset = 1; // shudder
385 for( unsigned i = 0; i < 5-layerOffset; i++ ) {
386 SGPropertyNode_ptr layerNode = cloudsNode->getChild(LAYER, i+layerOffset, true );
387 SGMetarCloud::Coverage coverage = i < metarClouds.size() ? metarClouds[i].getCoverage() : SGMetarCloud::COVERAGE_CLEAR;
389 i >= metarClouds.size() || coverage == SGMetarCloud::COVERAGE_CLEAR ?
391 metarClouds[i].getAltitude_ft() + _station_elevation;
393 layerNode->setDoubleValue( "alpha", 1.0 );
394 layerNode->setStringValue( "coverage", coverage_string[coverage] );
395 layerNode->setDoubleValue( "coverage-type", SGCloudLayer::getCoverageType(coverage_string[coverage]) );
396 layerNode->setDoubleValue( "elevation-ft", elevation );
397 layerNode->setDoubleValue( "thickness-ft", thickness_value[coverage]);
398 layerNode->setDoubleValue( "span-m", 40000 );
399 layerNode->setDoubleValue( "visibility-m", 50.0 );
403 _rain = m->getRain();
404 _hail = m->getHail();
405 _snow = m->getSnow();
406 _snow_cover = m->getSnowCover();
407 _metarValidNode->setBoolValue(true);
410 void MetarProperties::setStationId( const std::string & value )
412 set_station_id(simgear::strutils::strip(value).c_str());
415 double MetarProperties::get_magnetic_variation_deg() const
417 return _magneticVariation->get_variation_deg( _station_longitude, _station_latitude, _station_elevation );
420 double MetarProperties::get_magnetic_dip_deg() const
422 return _magneticVariation->get_dip_deg( _station_longitude, _station_latitude, _station_elevation );
425 static inline void calc_wind_hs( double north_fps, double east_fps, int & heading_deg, double & speed_kt )
427 speed_kt = sqrt((north_fps)*(north_fps)+(east_fps)*(east_fps)) * 3600.0 / (SG_NM_TO_METER * SG_METER_TO_FEET);
428 heading_deg = SGMiscd::roundToInt(
429 SGMiscd::normalizeAngle2( atan2( east_fps, north_fps ) ) * SGD_RADIANS_TO_DEGREES );
432 void MetarProperties::set_wind_from_north_fps( double value )
434 _wind_from_north_fps = value;
435 calc_wind_hs( _wind_from_north_fps, _wind_from_east_fps, _base_wind_dir, _wind_speed );
438 void MetarProperties::set_wind_from_east_fps( double value )
440 _wind_from_east_fps = value;
441 calc_wind_hs( _wind_from_north_fps, _wind_from_east_fps, _base_wind_dir, _wind_speed );
444 static inline void calc_wind_ne( double heading_deg, double speed_kt, double & north_fps, double & east_fps )
446 double speed_fps = speed_kt * SG_NM_TO_METER * SG_METER_TO_FEET / 3600.0;
447 north_fps = speed_fps * cos(heading_deg * SGD_DEGREES_TO_RADIANS);
448 east_fps = speed_fps * sin(heading_deg * SGD_DEGREES_TO_RADIANS);
451 void MetarProperties::set_base_wind_dir( double value )
453 _base_wind_dir = value;
454 calc_wind_ne( (double)_base_wind_dir, _wind_speed, _wind_from_north_fps, _wind_from_east_fps );
457 void MetarProperties::set_wind_speed( double value )
460 calc_wind_ne( (double)_base_wind_dir, _wind_speed, _wind_from_north_fps, _wind_from_east_fps );
464 } // namespace Environment