Function get_forward_offset

src/transformations/vertoffset.cpp:47–52

// Slope"

static double get_forward_offset(const PJ *P, double phi, double lam) {
    const struct pj_opaque_vertoffset *Q =
        (const struct pj_opaque_vertoffset *)P->opaque;
    return Q->zoff + Q->slope_lat * Q->rho0 * (phi - P->phi0) +
           Q->slope_lon * Q->nu0 * lam * cos(phi);
}

static PJ_XYZ forward_3d(PJ_LPZ lpz, PJ *P) {
    PJ_XYZ xyz;