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),
141 _magneticVariation(new MagneticVariation())
143 // Hack to avoid static initialization order problems on OSX
144 if( coverage_string.empty() ) {
145 coverage_string.push_back(SGCloudLayer::SG_CLOUD_CLEAR_STRING);
146 coverage_string.push_back(SGCloudLayer::SG_CLOUD_FEW_STRING);
147 coverage_string.push_back(SGCloudLayer::SG_CLOUD_SCATTERED_STRING);
148 coverage_string.push_back(SGCloudLayer::SG_CLOUD_BROKEN_STRING);
149 coverage_string.push_back(SGCloudLayer::SG_CLOUD_OVERCAST_STRING);
151 // don't tie metar-valid, so listeners get triggered
152 _metarValidNode->setBoolValue( false );
153 _tiedProperties.setRoot( _rootNode );
154 _tiedProperties.Tie("data", this, &MetarProperties::get_metar, &MetarProperties::set_metar );
155 _tiedProperties.Tie("station-id", this, &MetarProperties::get_station_id, &MetarProperties::set_station_id );
156 _tiedProperties.Tie("station-elevation-ft", &_station_elevation );
157 _tiedProperties.Tie("station-latitude-deg", &_station_latitude );
158 _tiedProperties.Tie("station-longitude-deg", &_station_longitude );
159 _tiedProperties.Tie("station-magnetic-variation-deg", this, &MetarProperties::get_magnetic_variation_deg );
160 _tiedProperties.Tie("station-magnetic-dip-deg", this, &MetarProperties::get_magnetic_dip_deg );
161 _tiedProperties.Tie("min-visibility-m", &_min_visibility );
162 _tiedProperties.Tie("max-visibility-m", &_max_visibility );
163 _tiedProperties.Tie("base-wind-range-from", &_base_wind_range_from );
164 _tiedProperties.Tie("base-wind-range-to", &_base_wind_range_to );
165 _tiedProperties.Tie("base-wind-speed-kt", this, &MetarProperties::get_wind_speed, &MetarProperties::set_wind_speed );
166 _tiedProperties.Tie("base-wind-dir-deg", this, &MetarProperties::get_base_wind_dir, &MetarProperties::set_base_wind_dir );
167 _tiedProperties.Tie("base-wind-from-north-fps", this, &MetarProperties::get_wind_from_north_fps, &MetarProperties::set_wind_from_north_fps );
168 _tiedProperties.Tie("base-wind-from-east-fps",this, &MetarProperties::get_wind_from_east_fps, &MetarProperties::set_wind_from_east_fps );
169 _tiedProperties.Tie("gust-wind-speed-kt", &_gusts );
170 _tiedProperties.Tie("temperature-degc", &_temperature );
171 _tiedProperties.Tie("dewpoint-degc", &_dewpoint );
172 _tiedProperties.Tie("rel-humidity-norm", &_humidity );
173 _tiedProperties.Tie("pressure-inhg", &_pressure );
174 _tiedProperties.Tie("temperature-sea-level-degc", &_sea_level_temperature );
175 _tiedProperties.Tie("dewpoint-sea-level-degc", &_sea_level_dewpoint );
176 _tiedProperties.Tie("pressure-sea-level-inhg", &_sea_level_pressure );
177 _tiedProperties.Tie("rain-norm", &_rain );
178 _tiedProperties.Tie("hail-norm", &_hail );
179 _tiedProperties.Tie("snow-norm", &_snow);
180 _tiedProperties.Tie("snow-cover", &_snow_cover );
181 _tiedProperties.Tie("day", &_day );
182 _tiedProperties.Tie("hour", &_hour );
183 _tiedProperties.Tie("minute", &_minute );
184 _tiedProperties.Tie("decoded", this, &MetarProperties::get_decoded );
185 _tiedProperties.Tie("cavok", &_cavok );
188 MetarProperties::~MetarProperties()
190 delete _magneticVariation;
194 static const double thickness_value[] = { 0, 65, 600, 750, 1000 };
196 const char* MetarProperties::get_metar() const
198 if (!_metar) return "";
199 return _metar->getData();
202 void MetarProperties::set_metar( const char * metarString )
204 SGSharedPtr<FGMetar> m;
205 if ((metarString == NULL) || (strlen(metarString) == 0)) {
211 m = new FGMetar( metarString );
213 catch( sg_io_exception ) {
214 SG_LOG( SG_ENVIRONMENT, SG_WARN, "Can't parse metar: " << metarString );
215 _metarValidNode->setBoolValue(false);
222 void MetarProperties::setMetar( SGSharedPtr<FGMetar> m )
230 const vector<string> weather = m->getWeather();
231 for( vector<string>::const_iterator it = weather.begin(); it != weather.end(); ++it ) {
232 if( false == _decoded.empty() ) _decoded.append(", ");
233 _decoded.append(*it);
236 _min_visibility = m->getMinVisibility().getVisibility_m();
237 _max_visibility = m->getMaxVisibility().getVisibility_m();
239 const SGMetarVisibility *dirvis = m->getDirVisibility();
240 for ( int i = 0; i < 8; i++, dirvis++) {
241 SGPropertyNode *vis = _rootNode->getChild("visibility", i, true);
242 double v = dirvis->getVisibility_m();
244 vis->setDoubleValue("min-m", v);
245 vis->setDoubleValue("max-m", v);
248 set_base_wind_dir(m->getWindDir());
249 _base_wind_range_from = m->getWindRangeFrom();
250 _base_wind_range_to = m->getWindRangeTo();
251 set_wind_speed(m->getWindSpeed_kt());
253 _gusts = m->getGustSpeed_kt();
254 _temperature = m->getTemperature_C();
255 _dewpoint = m->getDewpoint_C();
256 _humidity = m->getRelHumidity();
257 _pressure = m->getPressure_inHg();
260 // 1. check the id given in the metar
261 FGAirport* a = FGAirport::findByIdent(m->getId());
263 // 2. if unknown, find closest airport with metar to current position
265 SGGeod pos = SGGeod::fromDeg(
266 fgGetDouble( "/position/longitude-deg", 0.0 ),
267 fgGetDouble( "/position/latitude-deg", 0.0 ) );
268 a = FGAirport::findClosest(pos, 10000.0, MetarAirportFilter::instance() );
271 // 3. otherwise use ground elevation
273 _station_elevation = a->getElevation();
274 const SGGeod & towerPosition = a->getTowerLocation();
275 _station_latitude = towerPosition.getLatitudeDeg();
276 _station_longitude = towerPosition.getLongitudeDeg();
277 _station_id = a->ident();
279 _station_elevation = fgGetDouble("/position/ground-elev-m", 0.0 ) * SG_METER_TO_FEET;
280 _station_latitude = fgGetDouble( "/position/latitude-deg", 0.0 );
281 _station_longitude = fgGetDouble( "/position/longitude-deg", 0.0 );
282 _station_id = "XXXX";
286 { // calculate sea level temperature, dewpoint and pressure
287 FGEnvironment dummy; // instantiate a dummy so we can leech a method
288 dummy.set_elevation_ft( _station_elevation );
289 dummy.set_temperature_degc( _temperature );
290 dummy.set_dewpoint_degc( _dewpoint );
291 _sea_level_temperature = dummy.get_temperature_sea_level_degc();
292 _sea_level_dewpoint = dummy.get_dewpoint_sea_level_degc();
294 double elevation_m = _station_elevation * SG_FEET_TO_METER;
295 double fieldPressure = FGAtmo::fieldPressure( elevation_m, _pressure * atmodel::inHg );
296 _sea_level_pressure = P_layer(0, elevation_m, fieldPressure, _temperature + atmodel::freezing, atmodel::ISA::lam0) / atmodel::inHg;
306 for( unsigned i = 0; i < 3; i++ ) {
307 SGPropertyNode_ptr n = _rootNode->getChild("weather", i, true );
308 vector<struct SGMetar::Weather> weather = m->getWeather2();
309 struct SGMetar::Weather * w = i < weather.size() ? &weather[i] : NULL;
310 n->getNode("intensity",true)->setIntValue( w != NULL ? w->intensity : 0 );
311 n->getNode("vincinity",true)->setBoolValue( w != NULL ? w->vincinity : false );
312 for( unsigned j = 0; j < 3; j++ ) {
314 const string & phenomenon = w != NULL && j < w->phenomena.size() ? w->phenomena[j].c_str() : "";
315 n->getChild( "phenomenon", j, true )->setStringValue( phenomenon );
317 const string & description = w != NULL && j < w->descriptions.size() ? w->descriptions[j].c_str() : "";
318 n->getChild( "description", j, true )->setStringValue( description );
320 // need to know later,
321 // if its fog(FG) (might be shallow(MI) or patches(BC)) or haze (HZ) or mist(BR)
322 if( phenomenon == "FG" ) isFG = true;
323 if( phenomenon == "HZ" ) isHZ = true;
324 if( phenomenon == "BR" ) isBR = true;
325 if( description == "MI" ) isMI = true;
326 if( description == "BC" ) isBC = true;
332 static const char * LAYER = "layer";
333 SGPropertyNode_ptr cloudsNode = _rootNode->getNode("clouds", true );
334 const vector<SGMetarCloud> & metarClouds = m->getClouds();
335 unsigned layerOffset = 0; // Oh, this is ugly!
337 // fog/mist/haze cloud layer does not work with 3d clouds yet :-(
338 bool setGroundCloudLayer = _rootNode->getBoolValue("set-ground-cloud-layer", false ) &&
339 false == (fgGetBool("/sim/rendering/shader-effects", false ) &&
340 fgGetBool("/sim/rendering/clouds3d-enable", false ) );
342 if( setGroundCloudLayer ) {
343 // create a cloud layer #0 starting at the ground if its fog, mist or haze
345 // make sure layer actually starts at ground and set it's bottom at a constant
346 // value below the station's elevation
347 const double LAYER_BOTTOM_STATION_OFFSET =
348 fgGetDouble( "/environment/params/fog-mist-haze-layer/offset-from-station-elevation-ft", -200 );
350 SGMetarCloud::Coverage coverage = SGMetarCloud::COVERAGE_NIL;
351 double thickness = 0;
355 coverage = SGMetarCloud::getCoverage( isBC ?
356 fgGetString( "/environment/params/fog-mist-haze-layer/fog-bc-2dlayer-coverage", SGMetarCloud::COVERAGE_SCATTERED_STRING ) :
357 fgGetString( "/environment/params/fog-mist-haze-layer/fog-2dlayer-coverage", SGMetarCloud::COVERAGE_BROKEN_STRING )
361 fgGetDouble("/environment/params/fog-mist-haze-layer/fog-shallow-thickness-ft",30) - LAYER_BOTTOM_STATION_OFFSET : // shallow fog, 10m/30ft
362 fgGetDouble("/environment/params/fog-mist-haze-layer/fog-thickness-ft",500) - LAYER_BOTTOM_STATION_OFFSET; // fog, 150m/500ft
363 alpha = fgGetDouble("/environment/params/fog-mist-haze-layer/fog-2dlayer-alpha", 1.0);
364 } else if( isBR ) { // mist
365 coverage = SGMetarCloud::getCoverage(fgGetString("/environment/params/fog-mist-haze-layer/mist-2dlayer-coverage", SGMetarCloud::COVERAGE_OVERCAST_STRING));
366 thickness = fgGetDouble("/environment/params/fog-mist-haze-layer/mist-thickness-ft",2000) - LAYER_BOTTOM_STATION_OFFSET;
367 alpha = fgGetDouble("/environment/params/fog-mist-haze-layer/mist-2dlayer-alpha",0.8);
368 } else if( isHZ ) { // haze
369 coverage = SGMetarCloud::getCoverage(fgGetString("/environment/params/fog-mist-haze-layer/mist-2dlayer-coverage", SGMetarCloud::COVERAGE_OVERCAST_STRING));
370 thickness = fgGetDouble("/environment/params/fog-mist-haze-layer/haze-thickness-ft",2000) - LAYER_BOTTOM_STATION_OFFSET;
371 alpha = fgGetDouble("/environment/params/fog-mist-haze-layer/haze-2dlayer-alpha",0.6);
374 if( coverage != SGMetarCloud::COVERAGE_NIL ) {
376 // if there is a layer above the fog, limit the top to one foot below that layer's bottom
377 if( metarClouds.size() > 0 && metarClouds[0].getCoverage() != SGMetarCloud::COVERAGE_CLEAR )
378 thickness = metarClouds[0].getAltitude_ft() - LAYER_BOTTOM_STATION_OFFSET - 1;
380 SGPropertyNode_ptr layerNode = cloudsNode->getChild(LAYER, 0, true );
381 layerNode->setDoubleValue( "coverage-type", SGCloudLayer::getCoverageType(coverage_string[coverage]) );
382 layerNode->setStringValue( "coverage", coverage_string[coverage] );
383 layerNode->setDoubleValue( "elevation-ft", _station_elevation + LAYER_BOTTOM_STATION_OFFSET );
384 layerNode->setDoubleValue( "thickness-ft", thickness );
385 layerNode->setDoubleValue( "visibility-m", _min_visibility );
386 layerNode->setDoubleValue( "alpha", alpha );
387 _min_visibility = _max_visibility =
388 fgGetDouble("/environment/params/fog-mist-haze-layer/visibility-above-layer-m",20000.0); // assume good visibility above the fog
389 layerOffset = 1; // shudder
393 for( unsigned i = 0; i < 5-layerOffset; i++ ) {
394 SGPropertyNode_ptr layerNode = cloudsNode->getChild(LAYER, i+layerOffset, true );
395 SGMetarCloud::Coverage coverage = i < metarClouds.size() ? metarClouds[i].getCoverage() : SGMetarCloud::COVERAGE_CLEAR;
397 i >= metarClouds.size() || coverage == SGMetarCloud::COVERAGE_CLEAR ?
399 metarClouds[i].getAltitude_ft() + _station_elevation;
401 layerNode->setDoubleValue( "alpha", 1.0 );
402 layerNode->setStringValue( "coverage", coverage_string[coverage] );
403 layerNode->setDoubleValue( "coverage-type", SGCloudLayer::getCoverageType(coverage_string[coverage]) );
404 layerNode->setDoubleValue( "elevation-ft", elevation );
405 layerNode->setDoubleValue( "thickness-ft", thickness_value[coverage]);
406 layerNode->setDoubleValue( "span-m", 40000 );
407 layerNode->setDoubleValue( "visibility-m", 50.0 );
411 _rain = m->getRain();
412 _hail = m->getHail();
413 _snow = m->getSnow();
414 _snow_cover = m->getSnowCover();
416 _hour = m->getHour();
417 _minute = m->getMinute();
418 _cavok = m->getCAVOK();
419 _metarValidNode->setBoolValue(true);
422 void MetarProperties::setStationId( const std::string & value )
424 set_station_id(simgear::strutils::strip(value).c_str());
427 double MetarProperties::get_magnetic_variation_deg() const
429 return _magneticVariation->get_variation_deg( _station_longitude, _station_latitude, _station_elevation );
432 double MetarProperties::get_magnetic_dip_deg() const
434 return _magneticVariation->get_dip_deg( _station_longitude, _station_latitude, _station_elevation );
437 static inline void calc_wind_hs( double north_fps, double east_fps, int & heading_deg, double & speed_kt )
439 speed_kt = sqrt((north_fps)*(north_fps)+(east_fps)*(east_fps)) * 3600.0 / (SG_NM_TO_METER * SG_METER_TO_FEET);
440 heading_deg = SGMiscd::roundToInt(
441 SGMiscd::normalizeAngle2( atan2( east_fps, north_fps ) ) * SGD_RADIANS_TO_DEGREES );
444 void MetarProperties::set_wind_from_north_fps( double value )
446 _wind_from_north_fps = value;
447 calc_wind_hs( _wind_from_north_fps, _wind_from_east_fps, _base_wind_dir, _wind_speed );
450 void MetarProperties::set_wind_from_east_fps( double value )
452 _wind_from_east_fps = value;
453 calc_wind_hs( _wind_from_north_fps, _wind_from_east_fps, _base_wind_dir, _wind_speed );
456 static inline void calc_wind_ne( double heading_deg, double speed_kt, double & north_fps, double & east_fps )
458 double speed_fps = speed_kt * SG_NM_TO_METER * SG_METER_TO_FEET / 3600.0;
459 north_fps = speed_fps * cos(heading_deg * SGD_DEGREES_TO_RADIANS);
460 east_fps = speed_fps * sin(heading_deg * SGD_DEGREES_TO_RADIANS);
463 void MetarProperties::set_base_wind_dir( double value )
465 _base_wind_dir = value;
466 calc_wind_ne( (double)_base_wind_dir, _wind_speed, _wind_from_north_fps, _wind_from_east_fps );
469 void MetarProperties::set_wind_speed( double value )
472 calc_wind_ne( (double)_base_wind_dir, _wind_speed, _wind_from_north_fps, _wind_from_east_fps );
476 } // namespace Environment