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| author | Charles Karney <charles.karney@sri.com> | 2020-10-27 10:02:27 -0400 |
|---|---|---|
| committer | Charles Karney <charles.karney@sri.com> | 2020-10-27 10:02:27 -0400 |
| commit | 94e36270ca393bd7b107bf690f09fd8ec1cd046b (patch) | |
| tree | dd153675742ead1db539f3b7d155b6bb95ba4d7c /src/tsfn.cpp | |
| parent | 6bd7c777f8e789f8ea34a6aa68104ab44a31beee (diff) | |
| download | PROJ-94e36270ca393bd7b107bf690f09fd8ec1cd046b.tar.gz PROJ-94e36270ca393bd7b107bf690f09fd8ec1cd046b.zip | |
Use nm units in builtins.gie. Remove backward looking comments in code.
Diffstat (limited to 'src/tsfn.cpp')
| -rw-r--r-- | src/tsfn.cpp | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/tsfn.cpp b/src/tsfn.cpp index a0960a66..8ed258d6 100644 --- a/src/tsfn.cpp +++ b/src/tsfn.cpp @@ -11,10 +11,13 @@ double pj_tsfn(double phi, double sinphi, double e) { * e = eccentricity of the ellipsoid (dimensionless) * Output: * ts = exp(-psi) where psi is the isometric latitude (dimensionless) + * = 1 / (tan(chi) + sec(chi)) * Here isometric latitude is defined by * psi = log( tan(pi/4 + phi/2) * * ( (1 - e*sin(phi)) / (1 + e*sin(phi)) )^(e/2) ) * = asinh(tan(phi)) - e * atanh(e * sin(phi)) + * = asinh(tan(chi)) + * chi = conformal latitude ***************************************************************************/ double cosphi = cos(phi); |