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71 lines
2.4 KiB
71 lines
2.4 KiB
// maidenheadR.ino Bob Larkin 12 Nov 2022
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// Built from the K. Goba double precision files.
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// Data types float precision, funtion unchanged, names have added 'f'
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char letterizeR(int x) {
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return (char) x + 65;
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}
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// Input lat, lon in degrees; Input grid locator size 4, 6, 8, or 10
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// Output grid square string pointer.
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char* get_mhf(float32_t lat, float32_t lon, int size) {
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static char locator[11];
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float32_t LON_F[]={20.0f, 2.0f, 0.0833333f, 0.008333f, 0.00034720833f};
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float32_t LAT_F[]={10.0f, 1.0f, 0.0416665f, 0.004166f, 0.00017358333f};
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int i;
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lon += 180.0f;
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lat += 90.0f;
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if (size <= 0 || size > 10) size = 6;
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size/=2; size*=2;
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for (i = 0; i < size/2; i++){
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if (i % 2 == 1) {
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locator[i*2] = (char)(lon/LON_F[i] + '0');
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locator[i*2+1] = (char)(lat/LAT_F[i] + '0');
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} else {
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locator[i*2] = letterizeR((int)(lon/LON_F[i]));
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locator[i*2+1] = letterizeR((int)(lat/LAT_F[i]));
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}
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lon = fmod(lon, LON_F[i]);
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lat = fmod(lat, LAT_F[i]);
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}
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locator[i*2]=0;
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return locator;
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}
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char* complete_mh(char* locator) {
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static char locator2[11] = "LL55LL55LL";
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int len = strlen(locator);
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if (len >= 10) return locator;
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memcpy(locator2, locator, strlen(locator));
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return locator2;
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}
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// Convert grid square string to longitude
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float32_t mh2lonf(char* locator) {
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float32_t field, square, subsquare, extsquare, precsquare;
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int len = strlen(locator);
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if (len > 10) return 0;
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if (len < 10) locator = complete_mh(locator);
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field = (locator[0] - 'A') * 20.0f;
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square = (locator[2] - '0') * 2.0f;
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subsquare = (locator[4] - 'A') / 12.0f;
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extsquare = (locator[6] - '0') / 120.0f;
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precsquare = (locator[8] - 'A') / 2880.0f;
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return field + square + subsquare + extsquare + precsquare - 180.0f;
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}
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// Convert grid square string to latitude
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float32_t mh2latf(char* locator) {
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float field, square, subsquare, extsquare, precsquare;
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int len = strlen(locator);
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if (len > 10) return 0;
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if (len < 10) locator = complete_mh(locator);
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field = (locator[1] - 'A') * 10.0f;
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square = (locator[3] - '0') * 1.0f;
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subsquare = (locator[5] - 'A') / 24.0f;
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extsquare = (locator[7] - '0') / 240.0f;
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precsquare = (locator[9] - 'A') / 5760.0f;
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return field + square + subsquare + extsquare + precsquare - 90;
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}
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