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| author | Charles Karney <charles.karney@sri.com> | 2020-10-26 19:03:26 -0400 |
|---|---|---|
| committer | Charles Karney <charles.karney@sri.com> | 2020-10-26 19:03:26 -0400 |
| commit | 6bd7c777f8e789f8ea34a6aa68104ab44a31beee (patch) | |
| tree | 5b71841c6d881096d212ceb3fe9eaa070e617af7 /src/projections/merc.cpp | |
| parent | 75a8436b2491dbc1eebb196ea42b961fd011a52e (diff) | |
| download | PROJ-6bd7c777f8e789f8ea34a6aa68104ab44a31beee.tar.gz PROJ-6bd7c777f8e789f8ea34a6aa68104ab44a31beee.zip | |
Fix/add some comments.
Diffstat (limited to 'src/projections/merc.cpp')
| -rw-r--r-- | src/projections/merc.cpp | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/projections/merc.cpp b/src/projections/merc.cpp index e5da3967..39685478 100644 --- a/src/projections/merc.cpp +++ b/src/projections/merc.cpp @@ -13,6 +13,8 @@ PROJ_HEAD(webmerc, "Web Mercator / Pseudo Mercator") "\n\tCyl, Ell\n\t"; static PJ_XY merc_e_forward (PJ_LP lp, PJ *P) { /* Ellipsoidal, forward */ PJ_XY xy = {0.0,0.0}; xy.x = P->k0 * lp.lam; + // Instead of calling tan and sin, call sin and cos which the compiler + // optimizes to a single call to sincos. double sphi = sin(lp.phi), cphi = cos(lp.phi); xy.y = P->k0 * (asinh(sphi/cphi) - P->e * atanh(P->e * sphi)); return xy; |