1 // metar interface class
3 // Written by Melchior FRANZ, started December 2003.
5 // Copyright (C) 2003 Melchior FRANZ - mfranz@aon.at
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 * Interface for encoded Meteorological Aerodrome Reports (METAR).
31 #include <simgear/io/sg_socket.hxx>
32 #include <simgear/debug/logstream.hxx>
33 #include <simgear/structure/exception.hxx>
37 #define NaN SGMetarNaN
40 * The constructor takes a Metar string, or a four-letter ICAO code. In the
41 * latter case the metar string is downloaded from
42 * http://weather.noaa.gov/pub/data/observations/metar/stations/.
43 * The constructor throws sg_io_exceptions on failure. The "METAR"
44 * keyword has no effect (apart from incrementing the group counter
45 * @a grpcount) and can be left away. A keyword "SPECI" is
48 * @param m ICAO station id or metar string
49 * @param proxy proxy host (optional; default: "")
50 * @param port proxy port (optional; default: "80")
51 * @param auth proxy authorization information (optional; default: "")
55 * SGMetar *m = new SGMetar("METAR KSFO 061656Z 19004KT 9SM SCT100 OVC200 08/03 A3013");
56 * double t = m->getTemperature_F();
59 * SGMetar n("KSFO", "proxy.provider.foo", "3128", "proxy-password");
60 * double d = n.getDewpoint_C();
63 SGMetar::SGMetar(const string& m, const string& proxy, const string& port,
64 const string& auth, const time_t time) :
86 if (m.length() == 4 && isalnum(m[0]) && isalnum(m[1]) && isalnum(m[2]) && isalnum(m[3])) {
87 for (int i = 0; i < 4; i++)
88 _icao[i] = toupper(m[i]);
90 _data = loadData(_icao, proxy, port, auth, time);
92 _data = new char[m.length() + 2]; // make room for " \0"
93 strcpy(_data, m.c_str());
102 if (!scanPreambleDate())
108 if (!scanId() || !scanDate()) {
110 throw sg_io_exception("metar data bogus ", sg_location(_url));
117 while (scanVisibility()) ;
118 while (scanRwyVisRange()) ;
119 while (scanWeather()) ;
120 while (scanSkyCondition()) ;
123 while (scanSkyCondition()) ;
124 while (scanRunwayReport()) ;
128 while (scanColorState()) ;
130 while (scanRunwayReport()) ;
136 throw sg_io_exception("metar data incomplete ", sg_location(_url));
144 * Clears lists and maps to discourage access after destruction.
155 void SGMetar::useCurrentDate()
158 time_t now_sec = time(0);
159 #if defined( _MSC_VER ) || defined ( __MINGW32__ )
160 now = *gmtime(&now_sec);
162 gmtime_r(&now_sec, &now);
164 _year = now.tm_year + 1900;
165 _month = now.tm_mon + 1;
170 * If called with "KSFO" loads data from
172 * http://weather.noaa.gov/pub/data/observations/metar/stations/KSFO.TXT.
174 * Throws sg_io_exception on failure. Gives up after waiting longer than 10 seconds.
176 * @param id four-letter ICAO Metar station code, e.g. "KSFO".
177 * @param proxy proxy host (optional; default: "")
178 * @param port proxy port (optional; default: "80")
179 * @param auth proxy authorization information (optional; default: "")
180 * @return pointer to Metar data string, allocated by new char[].
181 * @see rfc2068.txt for proxy spec ("Proxy-Authorization")
183 char *SGMetar::loadData(const char *id, const string& proxy, const string& port,
184 const string& auth, time_t time)
186 const int buflen = 512;
187 char buf[2 * buflen];
189 string host = proxy.empty() ? "weather.noaa.gov" : proxy;
190 string path = "/pub/data/observations/metar/stations/";
192 path += string(id) + ".TXT";
193 _url = "http://weather.noaa.gov" + path;
195 SGSocket *sock = new SGSocket(host, port.empty() ? "80" : port, "tcp");
196 sock->set_timeout(10000);
197 if (!sock->open(SG_IO_OUT)) {
199 throw sg_io_exception("cannot connect to ", sg_location(host));
204 get += "http://weather.noaa.gov";
206 sprintf(buf, "%ld", time);
207 get += path + " HTTP/1.0\015\012X-Time: " + buf + "\015\012";
210 get += "Proxy-Authorization: " + auth + "\015\012";
213 sock->writestring(get.c_str());
218 while ((i = sock->readline(buf, buflen))) {
219 if (i <= 2 && isspace(buf[0]) && (!buf[1] || isspace(buf[1])))
221 if (!strncmp(buf, "X-MetarProxy: ", 13))
225 i = sock->readline(buf, buflen);
227 sock->readline(&buf[i], buflen);
236 throw sg_io_exception("no metar data available from ",
239 char *metar = new char[strlen(b) + 2]; // make room for " \0"
246 * Replace any number of subsequent spaces by just one space, and add
247 * a trailing space. This makes scanning for things like "ALL RWY" easier.
249 void SGMetar::normalizeData()
252 for (src = dest = _data; (*dest++ = *src++); )
253 while (*src == ' ' && src[1] == ' ')
255 for (dest--; isspace(*--dest); ) ;
261 // \d\d\d\d/\d\d/\d\d
262 bool SGMetar::scanPreambleDate()
265 int year, month, day;
266 if (!scanNumber(&m, &year, 4))
270 if (!scanNumber(&m, &month, 2))
274 if (!scanNumber(&m, &day, 2))
276 if (!scanBoundary(&m))
287 bool SGMetar::scanPreambleTime()
291 if (!scanNumber(&m, &hour, 2))
295 if (!scanNumber(&m, &minute, 2))
297 if (!scanBoundary(&m))
307 bool SGMetar::scanType()
309 if (strncmp(_m, "METAR ", 6) && strncmp(_m, "SPECI ", 6))
318 bool SGMetar::scanId()
321 for (int i = 0; i < 4; m++, i++)
322 if (!(isalpha(*m) || isdigit(*m)))
324 if (!scanBoundary(&m))
326 strncpy(_icao, _m, 4);
335 bool SGMetar::scanDate()
338 int day, hour, minute;
339 if (!scanNumber(&m, &day, 2))
341 if (!scanNumber(&m, &hour, 2))
343 if (!scanNumber(&m, &minute, 2))
347 if (!scanBoundary(&m))
358 // (NIL|AUTO|COR|RTD)
359 bool SGMetar::scanModifier()
363 if (!strncmp(m, "NIL", 3)) {
367 if (!strncmp(m, "AUTO", 4)) // automatically generated
369 else if (!strncmp(m, "COR", 3)) // manually corrected
371 else if (!strncmp(m, "RTD", 3)) // routine delayed
375 if (!scanBoundary(&m))
384 // (\d{3}|VRB)\d{1,3}(G\d{2,3})?(KT|KMH|MPS)
385 bool SGMetar::scanWind()
389 if (!strncmp(m, "VRB", 3))
391 else if (!scanNumber(&m, &dir, 3))
395 if (!scanNumber(&m, &i, 2, 3))
402 if (!scanNumber(&m, &i, 2, 3))
407 if (!strncmp(m, "KT", 2))
408 m += 2, factor = SG_KT_TO_MPS;
409 else if (!strncmp(m, "KMH", 3))
410 m += 3, factor = SG_KMH_TO_MPS;
411 else if (!strncmp(m, "KPH", 3)) // ??
412 m += 3, factor = SG_KMH_TO_MPS;
413 else if (!strncmp(m, "MPS", 3))
414 m += 3, factor = 1.0;
417 if (!scanBoundary(&m))
421 _wind_speed = speed * factor;
423 _gust_speed = gust * factor;
430 bool SGMetar::scanVariability()
434 if (!scanNumber(&m, &from, 3))
438 if (!scanNumber(&m, &to, 3))
440 if (!scanBoundary(&m))
443 _wind_range_from = from;
450 bool SGMetar::scanVisibility()
451 // TODO: if only directed vis are given, do still set min/max
453 if (!strncmp(_m, "//// ", 5)) { // spec compliant?
462 int modifier = SGMetarVisibility::EQUALS;
463 // \d{4}(N|NE|E|SE|S|SW|W|NW)?
464 if (scanNumber(&m, &i, 4)) {
469 else if (*m == 'N') {
477 } else if (*m == 'S') {
487 i = 50, modifier = SGMetarVisibility::LESS_THAN;
489 i++, modifier = SGMetarVisibility::GREATER_THAN;
492 // M?(\d{1,2}|\d{1,2}/\d{1,2}|\d{1,2} \d{1,2}/\d{1,2})(SM|KM)
495 m++, modifier = SGMetarVisibility::LESS_THAN;
497 if (!scanNumber(&m, &i, 1, 2))
503 if (!scanNumber(&m, &i, 1, 2))
506 } else if (*m == ' ') {
509 if (!scanNumber(&m, &i, 1, 2))
513 if (!scanNumber(&m, &denom, 1, 2))
515 distance += (double)i / denom;
518 if (!strncmp(m, "SM", 2))
519 distance *= SG_SM_TO_METER, m += 2;
520 else if (!strncmp(m, "KM", 2))
521 distance *= 1000, m += 2;
525 if (!scanBoundary(&m))
528 SGMetarVisibility *v;
530 v = &_dir_visibility[dir / 45];
531 else if (_min_visibility._distance == NaN)
532 v = &_min_visibility;
534 v = &_max_visibility;
536 v->_distance = distance;
537 v->_modifier = modifier;
545 // R\d\d[LCR]?/([PM]?\d{4}V)?[PM]?\d{4}(FT)?[DNU]?
546 bool SGMetar::scanRwyVisRange()
553 if (!scanNumber(&m, &i, 2))
555 if (*m == 'L' || *m == 'C' || *m == 'R')
559 strncpy(id, _m + 1, i = m - _m - 1);
567 m++, r._min_visibility._modifier = SGMetarVisibility::GREATER_THAN;
569 m++, r._min_visibility._modifier = SGMetarVisibility::LESS_THAN;
570 if (!scanNumber(&m, &from, 4))
575 m++, r._max_visibility._modifier = SGMetarVisibility::GREATER_THAN;
577 m++, r._max_visibility._modifier = SGMetarVisibility::LESS_THAN;
578 if (!scanNumber(&m, &to, 4))
583 if (!strncmp(m, "FT", 2)) {
584 from = int(from * SG_FEET_TO_METER);
585 to = int(to * SG_FEET_TO_METER);
588 r._min_visibility._distance = from;
589 r._max_visibility._distance = to;
591 if (*m == '/') // this is not in the spec!
594 m++, r._min_visibility._tendency = SGMetarVisibility::DECREASING;
596 m++, r._min_visibility._tendency = SGMetarVisibility::STABLE;
598 m++, r._min_visibility._tendency = SGMetarVisibility::INCREASING;
600 if (!scanBoundary(&m))
604 _runways[id]._min_visibility = r._min_visibility;
605 _runways[id]._max_visibility = r._max_visibility;
611 static const struct Token special[] = {
612 { "NSW", "no significant weather" },
613 { "VCSH", "showers in the vicinity" },
614 { "VCTS", "thunderstorm in the vicinity" },
619 static const struct Token description[] = {
620 { "SH", "showers of" },
621 { "TS", "thunderstorm with" },
622 { "BC", "patches of" },
624 { "DR", "low drifting" },
625 { "FZ", "freezing" },
632 static const struct Token phenomenon[] = {
635 { "GS", "small hail and/or snow pellets" },
636 { "IC", "ice crystals" },
637 { "PE", "ice pellets" },
639 { "SG", "snow grains" },
641 { "UP", "unknown precipitation" },
643 { "DU", "widespread dust" },
645 { "FGBR", "fog bank" },
650 { "VA", "volcanic ash" },
651 { "DS", "duststorm" },
652 { "FC", "funnel cloud/tornado waterspout" },
653 { "PO", "well-developed dust/sand whirls" },
655 { "SS", "sandstorm" },
656 { "UP", "unknown" }, // ... due to failed automatic acquisition
661 // (+|-|VC)?(NSW|MI|PR|BC|DR|BL|SH|TS|FZ)?((DZ|RA|SN|SG|IC|PE|GR|GS|UP){0,3})(BR|FG|FU|VA|DU|SA|HZ|PY|PO|SQ|FC|SS|DS){0,3}
662 bool SGMetar::scanWeather()
666 const struct Token *a;
667 if ((a = scanToken(&m, special))) {
668 if (!scanBoundary(&m))
670 _weather.push_back(a->text);
678 m++, pre = "light ", intensity = 1;
680 m++, pre = "heavy ", intensity = 3;
681 else if (!strncmp(m, "VC", 2))
682 m += 2, post = "in the vicinity ";
684 pre = "moderate ", intensity = 2;
687 for (i = 0; i < 3; i++) {
688 if (!(a = scanToken(&m, description)))
690 weather += string(a->text) + " ";
692 for (i = 0; i < 3; i++) {
693 if (!(a = scanToken(&m, phenomenon)))
695 weather += string(a->text) + " ";
696 if (!strcmp(a->id, "RA"))
698 else if (!strcmp(a->id, "HA"))
700 else if (!strcmp(a->id, "SN"))
703 if (!weather.length())
705 if (!scanBoundary(&m))
708 weather = pre + weather + post;
709 weather.erase(weather.length() - 1);
710 _weather.push_back(weather);
716 static const struct Token cloud_types[] = {
717 { "AC", "altocumulus" },
718 { "ACC", "altocumulus castellanus" },
719 { "ACSL", "altocumulus standing lenticular" },
720 { "AS", "altostratus" },
721 { "CB", "cumulonimbus" },
722 { "CBMAM", "cumulonimbus mammatus" },
723 { "CC", "cirrocumulus" },
724 { "CCSL", "cirrocumulus standing lenticular" },
726 { "CS", "cirrostratus" },
728 { "CUFRA", "cumulus fractus" },
729 { "NS", "nimbostratus" },
730 { "SAC", "stratoaltocumulus" }, // guessed
731 { "SC", "stratocumulus" },
732 { "SCSL", "stratocumulus standing lenticular" },
734 { "STFRA", "stratus fractus" },
735 { "TCU", "towering cumulus" },
740 // (FEW|SCT|BKN|OVC|SKC|CLR|CAVOK|VV)([0-9]{3}|///)?[:cloud_type:]?
741 bool SGMetar::scanSkyCondition()
747 if (!strncmp(m, "CLR", i = 3) // clear
748 || !strncmp(m, "SKC", i = 3) // sky clear
749 || !strncmp(m, "NSC", i = 3) // no significant clouds
750 || !strncmp(m, "CAVOK", i = 5)) { // ceiling and visibility OK (implies 9999)
752 if (!scanBoundary(&m))
757 _clouds.push_back(cl);
765 if (!strncmp(m, "VV", i = 2)) // vertical visibility
767 else if (!strncmp(m, "FEW", i = 3))
769 else if (!strncmp(m, "SCT", i = 3))
771 else if (!strncmp(m, "BKN", i = 3))
773 else if (!strncmp(m, "OVC", i = 3))
779 if (!strncmp(m, "///", 3)) // vis not measurable (e.g. because of heavy snowing)
781 else if (scanBoundary(&m)) {
783 return true; // ignore single OVC/BKN/...
784 } else if (!scanNumber(&m, &i, 3))
787 if (cl._coverage == -1) {
788 if (!scanBoundary(&m))
790 if (i == -1) // 'VV///'
791 _vert_visibility._modifier = SGMetarVisibility::NOGO;
793 _vert_visibility._distance = i * 100 * SG_FEET_TO_METER;
799 cl._altitude = i * 100 * SG_FEET_TO_METER;
801 const struct Token *a;
802 if ((a = scanToken(&m, cloud_types))) {
804 cl._type_long = a->text;
806 if (!scanBoundary(&m))
808 _clouds.push_back(cl);
815 // M?[0-9]{2}/(M?[0-9]{2})? (spec)
816 // (M?[0-9]{2}|XX)/(M?[0-9]{2}|XX)? (Namibia)
817 bool SGMetar::scanTemperature()
820 int sign = 1, temp, dew;
821 if (!strncmp(m, "XX/XX", 5)) { // not spec compliant!
823 return scanBoundary(&_m);
828 if (!scanNumber(&m, &temp, 2))
834 if (!scanBoundary(&m)) {
835 if (!strncmp(m, "XX", 2)) // not spec compliant!
841 if (!scanNumber(&m, &dew, 2))
844 if (!scanBoundary(&m))
856 double SGMetar::getRelHumidity() const
858 if (_temp == NaN || _dewp == NaN)
860 double dewp = pow(10.0, 7.5 * _dewp / (237.7 + _dewp));
861 double temp = pow(10.0, 7.5 * _temp / (237.7 + _temp));
862 return dewp * 100 / temp;
867 // [AQ]\d{2}(\d{2}|//) (Namibia)
868 bool SGMetar::scanPressure()
875 factor = SG_INHG_TO_PA / 100;
881 if (!scanNumber(&m, &press, 2))
884 if (!strncmp(m, "//", 2)) // not spec compliant!
886 else if (scanNumber(&m, &i, 2))
890 if (!scanBoundary(&m))
892 _pressure = press * factor;
899 static const char *runway_deposit[] = {
913 static const char *runway_deposit_extent[] = {
914 0, "1-10%", "11-25%", 0, 0, "26-50%", 0, 0, 0, "51-100%"
918 static const char *runway_friction[] = {
920 "poor braking action",
921 "poor/medium braking action",
922 "medium braking action",
923 "medium/good braking action",
924 "good braking action",
926 "friction: unreliable measurement"
930 // \d\d(CLRD|[\d/]{4})(\d\d|//)
931 bool SGMetar::scanRunwayReport()
938 if (!scanNumber(&m, &i, 2))
943 strcpy(id, "REP"); // repetition of previous report
946 id[0] = i / 10 + '0', id[1] = i % 10 + '0', id[2] = 'R', id[3] = '\0';
948 id[0] = i / 10 + '0', id[1] = i % 10 + '0', id[2] = '\0';
950 if (!strncmp(m, "CLRD", 4)) {
951 m += 4; // runway cleared
952 r._deposit_string = "cleared";
954 if (scanNumber(&m, &i, 1)) {
956 r._deposit_string = runway_deposit[i];
957 } else if (*m == '/')
962 if (*m == '1' || *m == '2' || *m == '5' || *m == '9') { // extent of deposit
963 r._extent = *m - '0';
964 r._extent_string = runway_deposit_extent[*m - '0'];
965 } else if (*m != '/')
970 if (!strncmp(m, "//", 2))
972 else if (!scanNumber(&m, &i, 2))
976 r._depth = 0.0005; // < 1 mm deep (let's say 0.5 :-)
977 else if (i > 0 && i <= 90)
978 r._depth = i / 1000.0; // i mm deep
979 else if (i >= 92 && i <= 98)
980 r._depth = (i - 90) / 20.0;
982 r._comment = "runway not in use";
983 else if (i == -1) // no depth given ("//")
989 if (m[0] == '/' && m[1] == '/')
991 else if (!scanNumber(&m, &i, 2))
993 if (i >= 1 && i < 90) {
994 r._friction = i / 100.0;
995 } else if ((i >= 91 && i <= 95) || i == 99) {
996 r._friction_string = runway_friction[i - 90];
998 if (!scanBoundary(&m))
1001 _runways[id]._deposit = r._deposit;
1002 _runways[id]._deposit_string = r._deposit_string;
1003 _runways[id]._extent = r._extent;
1004 _runways[id]._extent_string = r._extent_string;
1005 _runways[id]._depth = r._depth;
1006 _runways[id]._friction = r._friction;
1007 _runways[id]._friction_string = r._friction_string;
1008 _runways[id]._comment = r._comment;
1015 // WS (ALL RWYS?|RWY ?\d\d[LCR]?)?
1016 bool SGMetar::scanWindShear()
1019 if (strncmp(m, "WS", 2))
1022 if (!scanBoundary(&m))
1025 if (!strncmp(m, "ALL", 3)) {
1027 if (!scanBoundary(&m))
1029 if (strncmp(m, "RWY", 3))
1034 if (!scanBoundary(&m))
1036 _runways["ALL"]._wind_shear = true;
1043 for (cnt = 0;; cnt++) { // ??
1044 if (strncmp(m, "RWY", 3))
1049 if (!scanNumber(&m, &i, 2))
1051 if (*m == 'L' || *m == 'C' || *m == 'R')
1053 strncpy(id, mm, i = m - mm);
1055 if (!scanBoundary(&m))
1057 _runways[id]._wind_shear = true;
1060 _runways["ALL"]._wind_shear = true;
1066 bool SGMetar::scanTrendForecast()
1069 if (strncmp(m, "NOSIG", 5))
1073 if (!scanBoundary(&m))
1080 // (BLU|WHT|GRN|YLO|AMB|RED)
1081 static const struct Token colors[] = {
1082 { "BLU", "Blue" }, // 2500 ft, 8.0 km
1083 { "WHT", "White" }, // 1500 ft, 5.0 km
1084 { "GRN", "Green" }, // 700 ft, 3.7 km
1085 { "YLO", "Yellow" }, // 300 ft, 1.6 km
1086 { "AMB", "Amber" }, // 200 ft, 0.8 km
1087 { "RED", "Red" }, // <200 ft, <0.8 km
1092 bool SGMetar::scanColorState()
1095 const struct Token *a;
1096 if (!(a = scanToken(&m, colors)))
1098 if (!scanBoundary(&m))
1100 //printf(Y"Code %s\n"N, a->text);
1106 bool SGMetar::scanRemark()
1108 if (strncmp(_m, "RMK", 3))
1111 if (!scanBoundary(&_m))
1115 if (!scanRunwayReport()) {
1116 while (*_m && !isspace(*_m))
1125 bool SGMetar::scanRemainder()
1128 if (!(strncmp(m, "NOSIG", 5))) {
1130 if (scanBoundary(&m))
1131 _m = m; //_comment.push_back("No significant tendency");
1134 if (!scanBoundary(&m))
1141 bool SGMetar::scanBoundary(char **s)
1143 if (**s && !isspace(**s))
1145 while (isspace(**s))
1151 int SGMetar::scanNumber(char **src, int *num, int min, int max)
1156 for (i = 0; i < min; i++) {
1160 *num = *num * 10 + *s++ - '0';
1162 for (; i < max && isdigit(*s); i++)
1163 *num = *num * 10 + *s++ - '0';
1169 // find longest match of str in list
1170 const struct Token *SGMetar::scanToken(char **str, const struct Token *list)
1172 const struct Token *longest = 0;
1173 int maxlen = 0, len;
1175 for (int i = 0; (s = list[i].id); i++) {
1177 if (!strncmp(s, *str, len) && len > maxlen) {
1187 void SGMetarCloud::set(double alt, int cov)
1195 void SGMetarVisibility::set(double dist, int dir, int mod, int tend)