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author | Eric S. Raymond <esr@thyrsus.com> | 2011-09-29 21:18:51 -0400 |
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committer | Eric S. Raymond <esr@thyrsus.com> | 2011-09-29 21:18:51 -0400 |
commit | 44c6a6b7f969e0c31044a6f478a2f6fdad392e92 (patch) | |
tree | d6a3b6cdefbb476726c73b3697b7b3025f695328 /cgps.c | |
parent | 104f47e1ebf631650bb7be15f2390c4632e82316 (diff) | |
download | gpsd-44c6a6b7f969e0c31044a6f478a2f6fdad392e92.tar.gz |
Refactoring and splint cleanup.
Diffstat (limited to 'cgps.c')
-rw-r--r-- | cgps.c | 80 |
1 files changed, 7 insertions, 73 deletions
@@ -131,74 +131,6 @@ static bool compass_flag = false; #define GPS_ERROR -2 /* low-level failure in GPS read */ #define GPS_TIMEOUT -3 /* low-level failure in GPS waiting */ -/* Convert true heading to magnetic. Taken from the Aviation - Formulary v1.43. Valid to within two degrees within the - continiental USA except for the following airports: MO49 MO86 MO50 - 3K6 02K and KOOA. AK correct to better than one degree. Western - Europe correct to within 0.2 deg. - - If you're not in one of these areas, I apologize, I don't have the - math to compute your varation. This is obviously extremely - floating-point heavy, so embedded people, beware of using. - - Note that there are issues with using magnetic heading. This code - does not account for the possibility of travelling into or out of - an area of valid calculation beyond forcing the magnetic conversion - off. A better way to communicate this to the user is probably - desirable (in case the don't notice the subtle change from "(mag)" - to "(true)" on their display). - */ -static float true2magnetic(double lat, double lon, double heading) -{ - /* Western Europe */ - /*@ -evalorder +relaxtypes @*/ - if ((lat > 36.0) && (lat < 68.0) && (lon > -10.0) && (lon < 28.0)) { - heading = - (10.4768771667158 - (0.507385322418858 * lon) + - (0.00753170031703826 * pow(lon, 2)) - - (1.40596203924748e-05 * pow(lon, 3)) - - (0.535560699962353 * lat) - + (0.0154348808069955 * lat * lon) - - (8.07756425110592e-05 * lat * pow(lon, 2)) - + (0.00976887198864442 * pow(lat, 2)) - - (0.000259163929798334 * lon * pow(lat, 2)) - - (3.69056939266123e-05 * pow(lat, 3)) + heading); - } - /* USA */ - else if ((lat > 24.0) && (lat < 50.0) && (lon > 66.0) && (lon < 125.0)) { - lon = 0.0 - lon; - heading = - ((-65.6811) + (0.99 * lat) + (0.0128899 * pow(lat, 2)) - - (0.0000905928 * pow(lat, 3)) + (2.87622 * lon) - - (0.0116268 * lat * lon) - (0.00000603925 * lon * pow(lat, 2)) - - (0.0389806 * pow(lon, 2)) - - (0.0000403488 * lat * pow(lon, 2)) + - (0.000168556 * pow(lon, 3)) + heading); - } - /* AK */ - else if ((lat > 54.0) && (lon > 130.0) && (lon < 172.0)) { - lon = 0.0 - lon; - heading = - (618.854 + (2.76049 * lat) - (0.556206 * pow(lat, 2)) + - (0.00251582 * pow(lat, 3)) - (12.7974 * lon) - + (0.408161 * lat * lon) + (0.000434097 * lon * pow(lat, 2)) - - (0.00602173 * pow(lon, 2)) - - (0.00144712 * lat * pow(lon, 2)) + - (0.000222521 * pow(lon, 3)) + heading); - } else { - /* We don't know how to compute magnetic heading for this - * location. */ - magnetic_flag = false; - } - - /* No negative headings. */ - if (heading < 0.0) - heading += 360.0; - - return (heading); - /*@ +evalorder -relaxtypes @*/ -} - /* Function to call when we're all done. Does a bit of clean-up. */ static void die(int sig) { @@ -584,15 +516,17 @@ static void update_gps_panel(struct gps_data_t *gpsdata) (void)mvwprintw(datawin, 5, DATAWIN_VALUE_OFFSET, "%-*s", 27, scr); /* Fill in the heading. */ - if (gpsdata->fix.mode >= MODE_2D && isnan(gpsdata->fix.track) == 0) - if (!magnetic_flag) { + if (gpsdata->fix.mode >= MODE_2D && isnan(gpsdata->fix.track) == 0) { + double magheading = true2magnetic(gpsdata->fix.latitude, + gpsdata->fix.longitude, + gpsdata->fix.track); + if (!magnetic_flag || isnan(magheading) != 0) { (void)snprintf(scr, sizeof(scr), "%.1f deg (true)", gpsdata->fix.track); } else { (void)snprintf(scr, sizeof(scr), "%.1f deg (mag) ", - true2magnetic(gpsdata->fix.latitude, - gpsdata->fix.longitude, - gpsdata->fix.track)); + magheading); + } } else (void)snprintf(scr, sizeof(scr), "n/a"); (void)mvwprintw(datawin, 6, DATAWIN_VALUE_OFFSET, "%-*s", 27, scr); |