Merge pull request #2397 from cffk/merc-update

Update Mercator projection, more accurate, faster

1 files changed, 9 insertions, 9 deletions

diff --git a/src/projections/gstmerc.cpp b/src/projections/gstmerc.cpp
index 808d9ef7..50814bb5 100644
--- a/src/projections/gstmerc.cpp
+++ b/src/projections/gstmerc.cpp
@@ -28,9 +28,9 @@ static PJ_XY gstmerc_s_forward (PJ_LP lp, PJ *P) {           /* Spheroidal, forw
     double L, Ls, sinLs1, Ls1;
 
     L = Q->n1*lp.lam;
-    Ls = Q->c + Q->n1 * log(pj_tsfn(-1.0 * lp.phi, -1.0 * sin(lp.phi), P->e));
+    Ls = Q->c + Q->n1 * log(pj_tsfn(-lp.phi, -sin(lp.phi), P->e));
     sinLs1 = sin(L) / cosh(Ls);
-    Ls1 = log(pj_tsfn(-1.0 * asin(sinLs1), 0.0, 0.0));
+    Ls1 = log(pj_tsfn(-asin(sinLs1), -sinLs1, 0.0));
     xy.x = (Q->XS + Q->n2*Ls1) * P->ra;
     xy.y = (Q->YS + Q->n2*atan(sinh(Ls) / cos(L))) * P->ra;
 
@@ -45,9 +45,9 @@ static PJ_LP gstmerc_s_inverse (PJ_XY xy, PJ *P) {           /* Spheroidal, inve
 
     L = atan(sinh((xy.x * P->a - Q->XS) / Q->n2) / cos((xy.y * P->a - Q->YS) / Q->n2));
     sinC = sin((xy.y * P->a - Q->YS) / Q->n2) / cosh((xy.x * P->a - Q->XS) / Q->n2);
-    LC = log(pj_tsfn(-1.0 * asin(sinC), 0.0, 0.0));
+    LC = log(pj_tsfn(-asin(sinC), -sinC, 0.0));
     lp.lam = L / Q->n1;
-    lp.phi = -1.0 * pj_phi2(P->ctx, exp((LC - Q->c) / Q->n1), P->e);
+    lp.phi = -pj_phi2(P->ctx, exp((LC - Q->c) / Q->n1), P->e);
 
     return lp;
 }
@@ -60,13 +60,13 @@ PJ *PROJECTION(gstmerc) {
     P->opaque = Q;
 
     Q->lamc = P->lam0;
-    Q->n1 = sqrt(1.0 + P->es * pow(cos(P->phi0), 4.0) / (1.0 - P->es));
+    Q->n1 = sqrt(1 + P->es * pow(cos(P->phi0), 4.0) / (1 - P->es));
     Q->phic = asin(sin(P->phi0) / Q->n1);
-    Q->c = log(pj_tsfn(-1.0 * Q->phic, 0.0, 0.0))
-         - Q->n1 * log(pj_tsfn(-1.0 * P->phi0, -1.0 * sin(P->phi0), P->e));
-    Q->n2 = P->k0 * P->a * sqrt(1.0 - P->es) / (1.0 - P->es * sin(P->phi0) * sin(P->phi0));
+    Q->c = log(pj_tsfn(-Q->phic, -sin(P->phi0) / Q->n1, 0.0))
+         - Q->n1 * log(pj_tsfn(-P->phi0, -sin(P->phi0), P->e));
+    Q->n2 = P->k0 * P->a * sqrt(1 - P->es) / (1 - P->es * sin(P->phi0) * sin(P->phi0));
     Q->XS = 0;
-    Q->YS = -1.0 * Q->n2 * Q->phic;
+    Q->YS = -Q->n2 * Q->phic;
 
     P->inv = gstmerc_s_inverse;
     P->fwd = gstmerc_s_forward;