//LatLong- UTM conversion.c //Lat Long - UTM, UTM - Lat Long conversions #include #include #include #include "constants.h" #include "LatLong-UTMconversion.h" /*Reference ellipsoids derived from Peter H. Dana's website- http://www.utexas.edu/depts/grg/gcraft/notes/datum/elist.html Department of Geography, University of Texas at Austin Internet: pdana@mail.utexas.edu 3/22/95 Source Defense Mapping Agency. 1987b. DMA Technical Report: Supplement to Department of Defense World Geodetic System 1984 Technical Report. Part I and II. Washington, DC: Defense Mapping Agency */ void LLtoUTM(int ReferenceEllipsoid, const double Lat, const double Long, double *UTMNorthing, double *UTMEasting, char* UTMZone) { //converts lat/long to UTM coords. Equations from USGS Bulletin 1532 //East Longitudes are positive, West longitudes are negative. //North latitudes are positive, South latitudes are negative //Lat and Long are in decimal degrees //Written by Chuck Gantz- chuck.gantz@globalstar.com double a = ellipsoid[ReferenceEllipsoid].EquatorialRadius; double eccSquared = ellipsoid[ReferenceEllipsoid].eccentricitySquared; double k0 = 0.9996; double LongOrigin; double eccPrimeSquared; double N, T, C, A, M; //Make sure the longitude is between -180.00 .. 179.9 double LongTemp = (Long+180)-(int)((Long+180)/360)*360-180; // -180.00 .. 179.9; double LatRad = Lat*deg2rad; double LongRad = LongTemp*deg2rad; double LongOriginRad; int ZoneNumber; ZoneNumber = (int)((LongTemp + 180)/6) + 1; if( Lat >= 56.0 && Lat < 64.0 && LongTemp >= 3.0 && LongTemp < 12.0 ) ZoneNumber = 32; // Special zones for Svalbard if( Lat >= 72.0 && Lat < 84.0 ) { if( LongTemp >= 0.0 && LongTemp < 9.0 ) ZoneNumber = 31; else if( LongTemp >= 9.0 && LongTemp < 21.0 ) ZoneNumber = 33; else if( LongTemp >= 21.0 && LongTemp < 33.0 ) ZoneNumber = 35; else if( LongTemp >= 33.0 && LongTemp < 42.0 ) ZoneNumber = 37; } LongOrigin = (ZoneNumber - 1)*6 - 180 + 3; //+3 puts origin in middle of zone LongOriginRad = LongOrigin * deg2rad; //compute the UTM Zone from the latitude and longitude sprintf(UTMZone, "%d%c", ZoneNumber, UTMLetterDesignator(Lat)); eccPrimeSquared = (eccSquared)/(1-eccSquared); N = a/sqrt(1-eccSquared*sin(LatRad)*sin(LatRad)); T = tan(LatRad)*tan(LatRad); C = eccPrimeSquared*cos(LatRad)*cos(LatRad); A = cos(LatRad)*(LongRad-LongOriginRad); M = a*((1 - eccSquared/4 - 3*eccSquared*eccSquared/64 - 5*eccSquared*eccSquared*eccSquared/256)*LatRad - (3*eccSquared/8 + 3*eccSquared*eccSquared/32 + 45*eccSquared*eccSquared*eccSquared/1024)*sin(2*LatRad) + (15*eccSquared*eccSquared/256 + 45*eccSquared*eccSquared*eccSquared/1024)*sin(4*LatRad) - (35*eccSquared*eccSquared*eccSquared/3072)*sin(6*LatRad)); *UTMEasting = (double)(k0*N*(A+(1-T+C)*A*A*A/6 + (5-18*T+T*T+72*C-58*eccPrimeSquared)*A*A*A*A*A/120) + 500000.0); *UTMNorthing = (double)(k0*(M+N*tan(LatRad)*(A*A/2+(5-T+9*C+4*C*C)*A*A*A*A/24 + (61-58*T+T*T+600*C-330*eccPrimeSquared)*A*A*A*A*A*A/720))); if(Lat < 0) *UTMNorthing += 10000000.0; //10000000 meter offset for southern hemisphere } char UTMLetterDesignator(double Lat) { //This routine determines the correct UTM letter designator for the given latitude //returns 'Z' if latitude is outside the UTM limits of 84N to 80S //Written by Chuck Gantz- chuck.gantz@globalstar.com char LetterDesignator; if((84 >= Lat) && (Lat >= 72)) LetterDesignator = 'X'; else if((72 > Lat) && (Lat >= 64)) LetterDesignator = 'W'; else if((64 > Lat) && (Lat >= 56)) LetterDesignator = 'V'; else if((56 > Lat) && (Lat >= 48)) LetterDesignator = 'U'; else if((48 > Lat) && (Lat >= 40)) LetterDesignator = 'T'; else if((40 > Lat) && (Lat >= 32)) LetterDesignator = 'S'; else if((32 > Lat) && (Lat >= 24)) LetterDesignator = 'R'; else if((24 > Lat) && (Lat >= 16)) LetterDesignator = 'Q'; else if((16 > Lat) && (Lat >= 8)) LetterDesignator = 'P'; else if(( 8 > Lat) && (Lat >= 0)) LetterDesignator = 'N'; else if(( 0 > Lat) && (Lat >= -8)) LetterDesignator = 'M'; else if((-8> Lat) && (Lat >= -16)) LetterDesignator = 'L'; else if((-16 > Lat) && (Lat >= -24)) LetterDesignator = 'K'; else if((-24 > Lat) && (Lat >= -32)) LetterDesignator = 'J'; else if((-32 > Lat) && (Lat >= -40)) LetterDesignator = 'H'; else if((-40 > Lat) && (Lat >= -48)) LetterDesignator = 'G'; else if((-48 > Lat) && (Lat >= -56)) LetterDesignator = 'F'; else if((-56 > Lat) && (Lat >= -64)) LetterDesignator = 'E'; else if((-64 > Lat) && (Lat >= -72)) LetterDesignator = 'D'; else if((-72 > Lat) && (Lat >= -80)) LetterDesignator = 'C'; else LetterDesignator = 'Z'; //This is here as an error flag to show that the Latitude is outside the UTM limits return LetterDesignator; } void UTMtoLL(int ReferenceEllipsoid, const double UTMNorthing, const double UTMEasting, const char* UTMZone, double *Lat, double *Long ) { //converts UTM coords to lat/long. Equations from USGS Bulletin 1532 //East Longitudes are positive, West longitudes are negative. //North latitudes are positive, South latitudes are negative //Lat and Long are in decimal degrees. //Written by Chuck Gantz- chuck.gantz@globalstar.com double k0 = 0.9996; double a = ellipsoid[ReferenceEllipsoid].EquatorialRadius; double eccSquared = ellipsoid[ReferenceEllipsoid].eccentricitySquared; double eccPrimeSquared; double e1 = (1-sqrt(1-eccSquared))/(1+sqrt(1-eccSquared)); double N1, T1, C1, R1, D, M; double LongOrigin; double mu, phi1, phi1Rad; double x, y; int ZoneNumber; char* ZoneLetter; int NorthernHemisphere; //1 for northern hemispher, 0 for southern x = UTMEasting - 500000.0; //remove 500,000 meter offset for longitude y = UTMNorthing; ZoneNumber = strtoul(UTMZone, &ZoneLetter, 10); if (*ZoneLetter == '\0') { NorthernHemisphere = 1; //no letter - assume northern hemisphere } else if((*ZoneLetter >= 'N' && *ZoneLetter <= 'X') || (*ZoneLetter >= 'n' && *ZoneLetter <= 'x')) { NorthernHemisphere = 1; //point is in northern hemisphere } else { NorthernHemisphere = 0; //point is in southern hemisphere y -= 10000000.0; //remove 10,000,000 meter offset used for southern hemisphere } LongOrigin = (ZoneNumber - 1)*6 - 180 + 3; //+3 puts origin in middle of zone eccPrimeSquared = (eccSquared)/(1-eccSquared); M = y / k0; mu = M/(a*(1-eccSquared/4-3*eccSquared*eccSquared/64-5*eccSquared*eccSquared*eccSquared/256)); phi1Rad = mu + (3*e1/2-27*e1*e1*e1/32)*sin(2*mu) + (21*e1*e1/16-55*e1*e1*e1*e1/32)*sin(4*mu) +(151*e1*e1*e1/96)*sin(6*mu); phi1 = phi1Rad*rad2deg; N1 = a/sqrt(1-eccSquared*sin(phi1Rad)*sin(phi1Rad)); T1 = tan(phi1Rad)*tan(phi1Rad); C1 = eccPrimeSquared*cos(phi1Rad)*cos(phi1Rad); R1 = a*(1-eccSquared)/pow(1-eccSquared*sin(phi1Rad)*sin(phi1Rad), 1.5); D = x/(N1*k0); *Lat = phi1Rad - (N1*tan(phi1Rad)/R1)*(D*D/2-(5+3*T1+10*C1-4*C1*C1-9*eccPrimeSquared)*D*D*D*D/24 +(61+90*T1+298*C1+45*T1*T1-252*eccPrimeSquared-3*C1*C1)*D*D*D*D*D*D/720); *Lat = *Lat * rad2deg; *Long = (D-(1+2*T1+C1)*D*D*D/6+(5-2*C1+28*T1-3*C1*C1+8*eccPrimeSquared+24*T1*T1) *D*D*D*D*D/120)/cos(phi1Rad); *Long = LongOrigin + *Long * rad2deg; }