/src/proj/src/projections/collg.cpp
Line | Count | Source (jump to first uncovered line) |
1 | | |
2 | | |
3 | | #include <math.h> |
4 | | |
5 | | #include "proj.h" |
6 | | #include "proj_internal.h" |
7 | | |
8 | | PROJ_HEAD(collg, "Collignon") "\n\tPCyl, Sph"; |
9 | 0 | #define FXC 1.12837916709551257390 |
10 | 0 | #define FYC 1.77245385090551602729 |
11 | 0 | #define ONEEPS 1.0000001 |
12 | | |
13 | 0 | static PJ_XY collg_s_forward(PJ_LP lp, PJ *P) { /* Spheroidal, forward */ |
14 | 0 | PJ_XY xy = {0.0, 0.0}; |
15 | 0 | (void)P; |
16 | 0 | xy.y = 1. - sin(lp.phi); |
17 | 0 | if (xy.y <= 0.) |
18 | 0 | xy.y = 0.; |
19 | 0 | else |
20 | 0 | xy.y = sqrt(xy.y); |
21 | 0 | xy.x = FXC * lp.lam * xy.y; |
22 | 0 | xy.y = FYC * (1. - xy.y); |
23 | 0 | return (xy); |
24 | 0 | } |
25 | | |
26 | 0 | static PJ_LP collg_s_inverse(PJ_XY xy, PJ *P) { /* Spheroidal, inverse */ |
27 | 0 | PJ_LP lp = {0.0, 0.0}; |
28 | 0 | lp.phi = xy.y / FYC - 1.; |
29 | 0 | lp.phi = 1. - lp.phi * lp.phi; |
30 | 0 | if (fabs(lp.phi) < 1.) |
31 | 0 | lp.phi = asin(lp.phi); |
32 | 0 | else if (fabs(lp.phi) > ONEEPS) { |
33 | 0 | proj_errno_set(P, PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN); |
34 | 0 | return lp; |
35 | 0 | } else { |
36 | 0 | lp.phi = lp.phi < 0. ? -M_HALFPI : M_HALFPI; |
37 | 0 | } |
38 | | |
39 | 0 | lp.lam = 1. - sin(lp.phi); |
40 | 0 | if (lp.lam <= 0.) |
41 | 0 | lp.lam = 0.; |
42 | 0 | else |
43 | 0 | lp.lam = xy.x / (FXC * sqrt(lp.lam)); |
44 | 0 | return (lp); |
45 | 0 | } |
46 | | |
47 | 4 | PJ *PJ_PROJECTION(collg) { |
48 | 4 | P->es = 0.0; |
49 | 4 | P->inv = collg_s_inverse; |
50 | 4 | P->fwd = collg_s_forward; |
51 | | |
52 | 4 | return P; |
53 | 4 | } |
54 | | |
55 | | #undef FXC |
56 | | #undef FYC |
57 | | #undef ONEEPS |