61 lines
1.8 KiB
C++
61 lines
1.8 KiB
C++
// do some test relating to the concept of "up"
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#include <simgear/compiler.h>
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#include STL_IOSTREAM
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#include <plib/sg.h>
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#include <simgear/constants.h>
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#include <simgear/math/sg_geodesy.hxx>
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SG_USING_STD(cout);
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SG_USING_STD(endl);
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int main() {
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// for each lat/lon given in goedetic coordinates, calculate
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// geocentric coordinates, cartesian coordinates, the local "up"
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// vector (based on original geodetic lat/lon), as well as the "Z"
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// intercept (for which 0 = center of earth)
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double lon = 0;
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double alt = 0;
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for ( double lat = 0; lat <= 90; lat += 5.0 ) {
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cout << "lon = " << lon << " geod lat = " << lat;
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double sl_radius, lat_geoc;
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sgGeodToGeoc( lat * SGD_DEGREES_TO_RADIANS, alt, &sl_radius, &lat_geoc );
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cout << " geoc lat = " << lat_geoc * SGD_RADIANS_TO_DEGREES << endl;
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Point3D pgd( lon * SGD_DEGREES_TO_RADIANS, lat * SGD_DEGREES_TO_RADIANS, 0.0 );
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Point3D pc = sgGeodToCart( pgd );
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cout << " cartesian = " << pc << endl;
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sgdMat4 GEOD_UP;
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sgdVec3 geod_up;
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sgdMakeRotMat4( GEOD_UP, lon, 0.0, -lat );
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sgdSetVec3( geod_up, GEOD_UP[0][0], GEOD_UP[0][1], GEOD_UP[0][2] );
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cout << " geod up = " << geod_up[0] << ", " << geod_up[1] << ", "
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<< geod_up[2] << endl;
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sgdMat4 GEOC_UP;
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sgdVec3 geoc_up;
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sgdMakeRotMat4( GEOC_UP, lon, 0.0, -lat_geoc * SGD_RADIANS_TO_DEGREES );
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sgdSetVec3( geoc_up, GEOC_UP[0][0], GEOC_UP[0][1], GEOC_UP[0][2] );
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cout << " geoc up = " << geoc_up[0] << ", " << geoc_up[1] << ", "
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<< geoc_up[2] << endl;
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double slope = geod_up[2] / geod_up[0];
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double intercept = pc.z() - slope * pc.x();
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cout << " Z intercept (based on geodetic up) = " << intercept << endl;
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slope = geoc_up[2] / geoc_up[0];
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intercept = pc.z() - slope * pc.x();
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cout << " Z intercept (based on geocentric up) = " << intercept << endl;
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}
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return 0;
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}
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