diff options
Diffstat (limited to 'src/PJ_patterson.c')
| -rw-r--r-- | src/PJ_patterson.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/PJ_patterson.c b/src/PJ_patterson.c index 50ca0981..952b63ea 100644 --- a/src/PJ_patterson.c +++ b/src/PJ_patterson.c @@ -53,6 +53,8 @@ PROJ_HEAD(patterson, "Patterson Cylindrical") "\n\tCyl."; #define C4 (9.0 * K4) #define EPS11 1.0e-11 #define MAX_Y 1.790857183 +/* Not sure at all of the appropriate number for MAX_ITER... */ +#define MAX_ITER 100 static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ @@ -71,6 +73,7 @@ static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */ LP lp = {0.0,0.0}; double yc, tol, y2, f, fder; + int i; (void) P; yc = xy.y; @@ -82,7 +85,7 @@ static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */ xy.y = -MAX_Y; } - for (;;) { /* Newton-Raphson */ + for (i = MAX_ITER; i ; --i) { /* Newton-Raphson */ y2 = yc * yc; f = (yc * (K1 + y2 * y2 * (K2 + y2 * (K3 + K4 * y2)))) - xy.y; fder = C1 + y2 * y2 * (C2 + y2 * (C3 + C4 * y2)); @@ -91,6 +94,8 @@ static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */ break; } } + if( i == 0 ) + pj_ctx_set_errno( P->ctx, PJD_ERR_NON_CONVERGENT ); lp.phi = yc; /* longitude */ |