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code simplification: use atan2() [discussed with David]

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This commit is contained in:
mfranz 2005-04-22 06:41:07 +00:00
parent 73c1b5beb4
commit a14263a006
1 changed files with 3 additions and 19 deletions
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22
src/ATC/ATCutils.cxx
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@ -253,7 +253,7 @@ Point3D dclUpdatePosition(Point3D pos, double heading, double angle, double dist
// Get a heading in degrees from one lat/lon to another.
// This function assumes the world is spherical. If geodetic accuracy is required use the functions is sg_geodesy instead!
// Warning - at the moment we are not checking for identical points - currently it returns 90 in this instance.
// Warning - at the moment we are not checking for identical points - currently it returns 0 in this instance.
double GetHeadingFromTo(Point3D A, Point3D B) {
double latA = A.lat() * DCL_DEGREES_TO_RADIANS;
double lonA = A.lon() * DCL_DEGREES_TO_RADIANS;
@ -261,24 +261,8 @@ double GetHeadingFromTo(Point3D A, Point3D B) {
double lonB = B.lon() * DCL_DEGREES_TO_RADIANS;
double xdist = sin(lonB - lonA) * (double)SG_EQUATORIAL_RADIUS_M * cos((latA+latB)/2.0);
double ydist = sin(latB - latA) * (double)SG_EQUATORIAL_RADIUS_M;
if(xdist >= 0) {
if(ydist > 0) {
return(atan(xdist/ydist) * DCL_RADIANS_TO_DEGREES);
} else if (ydist == 0) {
return(90.0);
} else {
return(180.0 - atan(xdist/fabs(ydist)) * DCL_RADIANS_TO_DEGREES);
}
} else {
if(ydist > 0) {
return(360.0 - atan(fabs(xdist)/ydist) * DCL_RADIANS_TO_DEGREES);
} else if (ydist == 0) {
return(270.0);
} else {
return(180.0 + atan(xdist/ydist) * DCL_RADIANS_TO_DEGREES);
}
}
double heading = atan2(xdist, ydist) * DCL_RADIANS_TO_DEGREES;
return heading < 0.0 ? heading + 360 : heading;
}
// Given a heading (in degrees), bound it from 0 -> 360