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#define PJ_LIB__
#include <errno.h>
#include <math.h>
#include "proj.h"
#include "proj_internal.h"
PROJ_HEAD(col_urban, "Colombia Urban")
"\n\tMisc\n\th_0=";
// Notations and formulas taken from IOGP Publication 373-7-2 -
// Geomatics Guidance Note number 7, part 2 - March 2020
namespace { // anonymous namespace
struct pj_opaque {
double h0; // height of projection origin, divided by semi-major axis (a)
double rho0; // adimensional value, contrary to Guidance note 7.2
double A;
double B; // adimensional value, contrary to Guidance note 7.2
double C;
double D; // adimensional value, contrary to Guidance note 7.2
};
} // anonymous namespace
static PJ_XY col_urban_forward (PJ_LP lp, PJ *P) {
PJ_XY xy;
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
const double cosphi = cos(lp.phi);
const double sinphi = sin(lp.phi);
const double nu = 1. / sqrt(1 - P->es * sinphi * sinphi);
const double lam_nu_cosphi = lp.lam * nu * cosphi;
xy.x = Q->A * lam_nu_cosphi;
const double sinphi_m = sin(0.5 * (lp.phi + P->phi0));
const double rho_m = (1 - P->es) / pow(1 - P->es * sinphi_m * sinphi_m, 1.5);
const double G = 1 + Q->h0 / rho_m;
xy.y = G * Q->rho0 * ((lp.phi - P->phi0) + Q->B * lam_nu_cosphi * lam_nu_cosphi);
return xy;
}
static PJ_LP col_urban_inverse (PJ_XY xy, PJ *P) {
PJ_LP lp;
struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);
lp.phi = P->phi0 + xy.y / Q->D - Q->B * (xy.x / Q->C) * (xy.x / Q->C);
const double sinphi = sin(lp.phi);
const double nu = 1. / sqrt(1 - P->es * sinphi * sinphi);
lp.lam = xy.x / (Q->C * nu * cos(lp.phi));
return lp;
}
PJ *PROJECTION(col_urban) {
struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
if (nullptr==Q)
return pj_default_destructor (P, PROJ_ERR_OTHER /*ENOMEM*/);
P->opaque = Q;
const double h0_unscaled = pj_param(P->ctx, P->params, "dh_0").f;
Q->h0 = h0_unscaled / P->a;
const double sinphi0 = sin(P->phi0);
const double nu0 = 1. / sqrt(1 - P->es * sinphi0 * sinphi0);
Q->A = 1 + Q->h0 / nu0;
Q->rho0 = (1 - P->es) / pow(1 - P->es * sinphi0 * sinphi0, 1.5);
Q->B = tan(P->phi0) / (2 * Q->rho0 * nu0);
Q->C = 1 + Q->h0;
Q->D = Q->rho0 * (1 + Q->h0 / (1 - P->es));
P->fwd = col_urban_forward;
P->inv = col_urban_inverse;
return P;
}
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