wmweather+/convert.c

   1 #include "config.h"
   2
   3 /*  Copyright (C) 2002  Brad Jorsch <anomie@users.sourceforge.net>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18 */
  19
  20 #include <math.h>
  21 #if TM_IN_SYS_TIME
  22 # if TIME_WITH_SYS_TIME
  23 #  include <sys/time.h>
  24 #  include <time.h>
  25 # else
  26 #  if HAVE_SYS_TIME_H
  27 #   include <sys/time.h>
  28 #  else
  29 #   include <time.h>
  30 #  endif
  31 # endif
  32 #else
  33 #include <time.h>
  34 #endif
  35 #include <ctype.h>
  36 #include <string.h>
  37 #include <stdlib.h>
  38 #include "convert.h"
  39
  40 /*
  41  * To indicate unavailable data
  42  *   999 is used for temperature
  43  *   x<0 is used for rh, pressure, and windspeed
  44  */
  45
  46
  47 /* Calculations */
  48
  49 int rh_C(int temp_C, int dewpt_C){
  50     float f;
  51
  52     if(temp_C==999 || dewpt_C==999) return 999;
  53
  54     f=1782.75*(dewpt_C-temp_C)/((237.7+dewpt_C)*(237.7+temp_C));
  55     return round(pow(10, f+2));
  56 }
  57
  58 int rh_F(int temp_F, int dewpt_F){
  59     float f;
  60
  61     if(temp_F==999 || dewpt_F==999) return 999;
  62
  63     f=3208.95*(dewpt_F-temp_F)/((395.86+dewpt_F)*(395.86+temp_F));
  64     return round(pow(10, f+2));
  65 }
  66
  67 int heatindex_C(int temp_C, int rh){
  68 #if 1
  69     if(temp_C==999 || temp_C<21 || rh<0) return 999;
  70     return heatindex_F(temp_C2F(temp_C), rh);
  71 #else
  72     int temp2, rh2;
  73
  74     if(temp_C==999 || temp_C<38 || rh<0) return 999;
  75
  76     temp2=temp_C*temp_C;
  77     rh2=rh*rh;
  78     return round(16.18754948 + 2.900509394*temp_C - 0.0221545692*temp2 + 4.20938791*rh - 0.26300889*temp_C*rh + 0.0039811176*temp2*rh - 0.02956469*rh2 + 0.001305828*temp_C*rh2 - 6.4476e-06*temp2*rh2);
  79 #endif
  80 }
  81
  82 int heatindex_F(int temp_F, int rh){
  83     int temp2, temp3, rh2, rh3;
  84
  85     if(temp_F==999 || temp_F<70 || rh<0) return 999;
  86
  87     temp2=temp_F*temp_F;
  88     temp3=temp2*temp_F;
  89     rh2=rh*rh;
  90     rh3=rh2*rh;
  91     return round(16.923 + .185212*temp_F + 5.37941*rh - .100254*temp_F*rh + (9.41695e-3)*temp2 + (7.28898e-3)*rh2 + (3.45372e-4)*temp2*rh - (8.14971e-4)*temp_F*rh2 + (1.02102e-5)*temp2*rh2 - (3.8646e-5)*temp3 + (2.91583e-5)*rh3 + (1.42721e-6)*temp3*rh + (1.97483e-7)*temp_F*rh3 - (2.18429e-8)*temp3*rh2 + (8.43296e-10)*temp2*rh3 - (4.81975e-11)*temp3*rh3);
  92 #if 0
  93     return round(-42.379 + 2.04901523*temp_F + 10.14333127*rh - 0.22475541*temp_F*rh - .00683783*temp2 - .05481717*rh2 + .00122874*temp2*rh + .00085282*temp_F*rh2 - .00000199*temp2*rh2);
  94 #endif
  95 }
  96
  97 int windchill_C(int temp_C, int windspeed){
  98     if(temp_C==999 || windspeed<0) return 999;
  99
 100     return windchill_F(temp_C2F(temp_C), windspeed);
 101 }
 102
 103 int windchill_F(int temp_F, int windspeed){
 104     double ret;
 105     if(temp_F==999 || windspeed<0) return 999;
 106
 107     ret=35.74 + 0.6215*temp_F + (-35.75 + 0.4275*temp_F)*pow(windspeed*50292/57875.0, 0.16);
 108     if(ret>temp_F) return temp_F;
 109     return round(ret);
 110 }
 111
 112 /* Length Conversions */
 113
 114 int in2cm(int in){
 115     if(in<0) return in;
 116     return round(in*2.54);
 117 }
 118
 119 float m2mi(int meters){
 120     if(meters<0) return meters;
 121     return meters*125/201168;
 122 }
 123
 124 /* Windspeed Conversions */
 125
 126 int knots2mph(int knots){
 127     if(knots<0) return knots;
 128     return round(knots*57875/50292.0);
 129 }
 130
 131 int knots2kph(int knots){
 132     if(knots<0) return knots;
 133     return round(knots*463/250.0);
 134 }
 135
 136 int kph2knots(int kph){
 137     if(kph<0) return kph;
 138     return round(kph*250/463.0);
 139 }
 140
 141 int knots2mps(int knots){
 142     if(knots<0) return knots;
 143     return round(knots*463/900.0);
 144 }
 145
 146 int mps2knots(int mps){
 147     if(mps<0) return mps;
 148     return round(mps*900/463.0);
 149 }
 150
 151 int knots2beaufort(int knots){
 152     if(knots<0) return knots;
 153     if(knots<1) return 0;
 154     if(knots<=3) return 1;
 155     if(knots<=6) return 2;
 156     if(knots<=10) return 3;
 157     if(knots<=16) return 4;
 158     if(knots<=21) return 5;
 159     if(knots<=27) return 6;
 160     if(knots<=33) return 7;
 161     if(knots<=40) return 8;
 162     if(knots<=47) return 9;
 163     if(knots<=55) return 10;
 164     if(knots<=63) return 11;
 165     return 12;
 166 }
 167
 168
 169 /* Temperature Conversions */
 170
 171 int temp_C2F(int temp_C){
 172     if(temp_C==999) return 999;
 173     return round(temp_C*9/5.0+32);
 174 }
 175
 176 int temp_F2C(int temp_F){
 177     if(temp_F==999) return 999;
 178     return round((temp_F-32)*5/9.0);
 179 }
 180
 181
 182 /* Pressure Conversions */
 183
 184 float inHg2mmHg(float inHg){
 185     if(inHg<0) return inHg;
 186     return inHg*25.4;
 187 }
 188
 189 float inHg2hPa(float inHg){
 190     if(inHg<0) return inHg;
 191     return inHg*33.8639;
 192 }
 193
 194 float inHg2atm(float inHg){
 195     if(inHg<0) return inHg;
 196     return inHg*.033421052632;
 197 }
 198
 199 float hPa2inHg(float hPa){
 200     if(hPa<0) return hPa;
 201     return hPa/33.8639;
 202 }
 203
 204
 205 /* Time Conversions */
 206
 207 /* NOTE: y%400==100 because y=year-1900 */
 208 #define is_leap(y) (y%4==0 && (y%100!=0 || y%400==100))
 209
 210 /* mktime for UTC, more or less.
 211  * Differences:
 212  *   - no range checking
 213  *   - never recalculates tm_wday or tm_yday
 214  */
 215 time_t mkgmtime(struct tm *tm){
 216     static long msec[]={0, 2678400, 5097600, 7776000, 10368000, 13046400, 15638400, 18316800, 20995200, 23587200, 26265600, 28857600};
 217     time_t t;
 218     int i;
 219
 220     t=0;
 221     if(tm->tm_year>70){
 222         for(i=70; i<tm->tm_year; i++){
 223             t+=31536000;
 224             if(is_leap(i)) t+=86400;
 225         }
 226     } else if(tm->tm_year<70){
 227         for(i=69; i>=tm->tm_year; i--){
 228             t-=31536000;
 229             if(is_leap(i)) t-=86400;
 230         }
 231     }
 232     t+=msec[tm->tm_mon];
 233     if(tm->tm_mon>1 && is_leap(tm->tm_year)) t+=86400;
 234     t+=(((tm->tm_mday-1)*24+tm->tm_hour)*60+tm->tm_min)*60+tm->tm_sec;
 235
 236     return t;
 237 }
 238
 239 int utc2local(int hm, int *month, int *day, int *year, int *wday){
 240     time_t t=time(NULL);
 241     struct tm *tm;
 242
 243     tm=gmtime(&t);
 244     tm->tm_hour=hm/100;
 245     tm->tm_min=hm%100;
 246     if(month!=NULL && *month!=-1) tm->tm_mon=*month-1;
 247     if(day!=NULL && *day!=-1) tm->tm_mday=*day;
 248     if(year!=NULL && *year!=-1) tm->tm_year=*year;
 249
 250     t=mkgmtime(tm);
 251     tm=localtime(&t);
 252
 253     if(month!=NULL) *month=tm->tm_mon+1;
 254     if(day!=NULL) *day=tm->tm_mday;
 255     if(year!=NULL) *year=tm->tm_year;
 256     if(wday!=NULL) *wday=tm->tm_wday;
 257     return tm->tm_hour*100+tm->tm_min;
 258 }
 259
 260 int local2utc(int hm, int *month, int *day, int *year, int *wday){
 261     time_t t=time(NULL);
 262     struct tm *tm;
 263
 264     tm=localtime(&t);
 265     tm->tm_hour=hm/100;
 266     tm->tm_min=hm%100;
 267     if(month!=NULL && *month!=-1) tm->tm_mon=*month-1;
 268     if(day!=NULL && *day!=-1) tm->tm_mday=*day;
 269     if(year!=NULL && *year!=-1) tm->tm_year=*year;
 270
 271     t=mktime(tm);
 272     tm=gmtime(&t);
 273
 274     if(month!=NULL) *month=tm->tm_mon+1;
 275     if(day!=NULL) *day=tm->tm_mday;
 276     if(year!=NULL) *year=tm->tm_year;
 277     if(wday!=NULL) *wday=tm->tm_wday;
 278     return tm->tm_hour*100+tm->tm_min;
 279 }
 280
 281 void fix_date(int *month, int *day, int *year, int *wday){
 282     time_t t=time(NULL);
 283     struct tm *tm;
 284
 285     tm=gmtime(&t);
 286     if(month!=NULL && *month!=-1) tm->tm_mon=*month-1;
 287     if(day!=NULL && *day!=-1) tm->tm_mday=*day;
 288     if(year!=NULL && *year!=-1) tm->tm_year=*year;
 289
 290     t=mkgmtime(tm);
 291     tm=gmtime(&t);
 292
 293     if(month!=NULL) *month=tm->tm_mon+1;
 294     if(day!=NULL) *day=tm->tm_mday;
 295     if(year!=NULL) *year=tm->tm_year;
 296     if(wday!=NULL) *wday=tm->tm_wday;
 297 }
 298
 299 int hm2min(int hm){
 300     return hm/100*60+hm%100;
 301 }
 302
 303 /* Letter Case (destructive!) */
 304
 305 char *str_upper(char *str){
 306     char *c;
 307
 308     for(c=str; *c!='\0'; c++){
 309         *c=toupper(*c);
 310     }
 311     return str;
 312 }
 313
 314 char *str_lower(char *str){
 315     char *c;
 316
 317     for(c=str; *c!='\0'; c++){
 318         *c=tolower(*c);
 319     }
 320     return str;
 321 }
 322
 323
 324 /* Angle conversions */
 325
 326 /* Convert radian angle to degrees */
 327 double rad2deg(double angle) {
 328     return 180.0*angle/PI;
 329 }
 330
 331 /* Convert degree angle to radians */
 332 double deg2rad(double angle) {
 333     return PI*angle/180.0;
 334 }
 335
 336
 337 /* Date conversions */
 338
 339 /*  Numerical day-of-year from month, day and year */
 340 int mdy2doy(int mn, int dy, int y) {
 341     return 275*mn/9 - ((y%4==0 && (y%100!=0 || y%400==100))?1:2)*(mn + 9)/12 + dy-30;
 342 }
 343
 344 /* Julian day from month/day/year */
 345 double mdy2jd(int year, int month, int day) {
 346     int A, B;
 347
 348     year+=1900;
 349     if (month <= 2) {
 350         year -= 1;
 351         month += 12;
 352     }
 353     A=year/100;
 354     B=2 - A + A/4;
 355
 356     return (int)(365.25*(year + 4716)) + (int)(30.6001*(month+1)) + day + B - 1524.5;
 357 }
 358
 359 /* convert Julian Day to centuries since J2000.0. */
 360 double jd2jcent(double jd) {
 361     return (jd - 2451545.0)/36525.0;
 362 }
 363
 364 /* convert centuries since J2000.0 to Julian Day. */
 365 double jcent2jd(double t) {
 366     return t * 36525.0 + 2451545.0;
 367 }
 368
 369
 370 /* Lat/Long conversions */
 371
 372 static double parse_dd_or_dms(char *s, char **e){
 373     double deg;
 374
 375     *e=s;
 376     if(strchr(s, 'x') || strchr(s, 'X')) return NAN;
 377     if(!strchr(s, '\'')){
 378         if(!isdigit(*s) && *s!='.') return NAN;
 379         return strtod(s, e);
 380     }
 381
 382     if(!isdigit(*s)) return NAN;
 383     deg=strtol(s, e, 10);
 384     if(*e==s || *e==NULL || **e!='\'') return deg;
 385     s=++(*e);
 386     if(!isdigit(*s)) return deg;
 387     deg+=strtol(s, e, 10)/60.0;
 388     if(*e==s || *e==NULL || **e!='\'') return deg;
 389     s=++(*e);
 390     if(!isdigit(*s) && *s!='.') return NAN;
 391     deg+=strtod(s, e)/3600.0;
 392     if(*e!=s && *e!=NULL && **e=='\'') (*e)++;
 393     return deg;
 394 }
 395
 396 int str2dd(char *s, double *lat, double *lon){
 397     char *e;
 398     int dir=0;
 399     char c;
 400
 401     c=toupper(*s);
 402     if(c=='+' || c=='N'){
 403         s++; dir=1;
 404     }
 405     if(c=='-' || c=='S'){
 406         s++; dir=-1;
 407     }
 408
 409     *lat=parse_dd_or_dms(s, &e);
 410     if(isnan(*lat) || e==NULL || e==s || *e=='\0') return 0;
 411     if(!dir){
 412         c=toupper(*e);
 413         if(c=='N') dir=1;
 414         if(c=='S') dir=-1;
 415         if(dir) e++;
 416     }
 417     if(dir<0) *lat=-*lat;
 418
 419     while(isspace(*e)) e++;
 420     if(*e=='\0') return 0;
 421
 422     s=e; dir=0;
 423     c=toupper(*s);
 424     if(c=='+' || c=='W'){
 425         s++; dir=1;
 426     }
 427     if(c=='-' || c=='E'){
 428         s++; dir=-1;
 429     }
 430
 431     *lon=parse_dd_or_dms(s, &e);
 432     if(isnan(*lon) || e==s) return 0;
 433     if(e==NULL || *e=='\0') return 1;
 434     if(dir==0){
 435         c=toupper(*e);
 436         if(c=='W') dir=1;
 437         if(c=='E') dir=-1;
 438         if(dir!=0) e++;
 439     }
 440     if(dir<0) *lon=-*lon;
 441
 442     return (*e=='\0');
 443 }