void _hex2dToGeo()

in h3_faceijk.c [438:473]

• 19 lines of code
• 7 McCabe index (conditional complexity)

void _hex2dToGeo(const Vec2d *v, int face, int res, int substrate, LatLng *g) {
    // calculate (r, theta) in hex2d
    double r = _v2dMag(v);

    if (r < EPSILON) {
        *g = faceCenterGeo[face];
        return;
    }

    double theta = atan2(v->y, v->x);

    // scale for current resolution length u
    for (int i = 0; i < res; i++) r *= M_RSQRT7;

    // scale accordingly if this is a substrate grid
    if (substrate) {
        r *= M_ONETHIRD;
        if (isResolutionClassIII(res)) r *= M_RSQRT7;
    }

    r *= RES0_U_GNOMONIC;

    // perform inverse gnomonic scaling of r
    r = atan(r);

    // adjust theta for Class III
    // if a substrate grid, then it's already been adjusted for Class III
    if (!substrate && isResolutionClassIII(res))
        theta = _posAngleRads(theta + M_AP7_ROT_RADS);

    // find theta as an azimuth
    theta = _posAngleRads(faceAxesAzRadsCII[face][0] - theta);

    // now find the point at (r,theta) from the face center
    _geoAzDistanceRads(&faceCenterGeo[face], theta, r, g);
}