diff options
| -rw-r--r-- | src/projections/tmerc.cpp | 6 | ||||
| -rw-r--r-- | test/gie/builtins.gie | 124 |
2 files changed, 128 insertions, 2 deletions
diff --git a/src/projections/tmerc.cpp b/src/projections/tmerc.cpp index 8cae9968..2d13b064 100644 --- a/src/projections/tmerc.cpp +++ b/src/projections/tmerc.cpp @@ -203,11 +203,13 @@ static PJ_LP approx_s_inv (PJ_XY xy, PJ *P) { return proj_coord_error().lp; } g = .5 * (h - 1. / h); - h = cos (P->phi0 + xy.y / Q->esp); + /* D, as in equation 8-8 of USGS "Map Projections - A Working Manual" */ + const double D = P->phi0 + xy.y / Q->esp; + h = cos (D); lp.phi = asin(sqrt((1. - h * h) / (1. + g * g))); /* Make sure that phi is on the correct hemisphere when false northing is used */ - if (xy.y < 0. && -lp.phi+P->phi0 < 0.0) lp.phi = -lp.phi; + lp.phi = copysign(lp.phi, D); lp.lam = (g != 0.0 || h != 0.0) ? atan2 (g, h) : 0.; return lp; diff --git a/test/gie/builtins.gie b/test/gie/builtins.gie index add5d925..0f86bed2 100644 --- a/test/gie/builtins.gie +++ b/test/gie/builtins.gie @@ -5782,6 +5782,130 @@ accept -200 -100 expect -0.001790493 -0.000895247 ------------------------------------------------------------------------------- +# Approx tmerc on a almost spherical ellipsoid, lat_0 north hemisphere + +operation +proj=tmerc +a=6400000 +rf=1e12 +k=0.9 +lat_0=40 +approx +------------------------------------------------------------------------------- +tolerance 0.1 mm + +accept 0 -30 +expect 0 -7037167.5440 +roundtrip 1 + +accept 1 -30 +expect 87064.5795 -7037547.4590 +roundtrip 1 + +accept -1 -30 +expect -87064.5795 -7037547.4590 +roundtrip 1 + +accept 0 30 +expect 0 -1005309.6491 +roundtrip 1 + +accept 0 40 +expect 0 0 +roundtrip 1 + +accept 1 41 +expect 75872.2182 100965.3718 +roundtrip 1 + +------------------------------------------------------------------------------- +# Approx tmerc on a sphere, lat_0 north hemisphere + +operation +proj=tmerc +R=6400000 +k=0.9 +lat_0=40 +------------------------------------------------------------------------------- +tolerance 0.1 mm + +accept 0 -30 +expect 0 -7037167.5440 +roundtrip 1 + +accept 1 -30 +expect 87064.5795 -7037547.4590 +roundtrip 1 + +accept -1 -30 +expect -87064.5795 -7037547.4590 +roundtrip 1 + +accept 0 30 +expect 0 -1005309.6491 +roundtrip 1 + +accept 0 40 +expect 0 0 +roundtrip 1 + +accept 1 41 +expect 75872.2182 100965.3718 +roundtrip 1 + +------------------------------------------------------------------------------- +# Approx tmerc on a almost spherical ellipsoid, lat_0 south hemisphere + +operation +proj=tmerc +a=6400000 +rf=1e12 +k=0.9 +lat_0=-40 +approx +------------------------------------------------------------------------------- +tolerance 0.1 mm + +accept 0 -30 +expect 0 1005309.6491 +roundtrip 1 + +accept 1 -30 +expect 87064.5795 1004929.7341 +roundtrip 1 + +accept -1 -30 +expect -87064.5795 1004929.7341 +roundtrip 1 + +accept 0 30 +expect 0 7037167.5440 +roundtrip 1 + +accept 0 -40 +expect 0 0 +roundtrip 1 + +accept 1 -41 +expect 75872.2182 -100965.3718 +roundtrip 1 + +------------------------------------------------------------------------------- +# Approx tmerc on a sphere, lat_0 south hemisphere + +operation +proj=tmerc +R=6400000 +k=0.9 +lat_0=-40 +------------------------------------------------------------------------------- +tolerance 0.1 mm + +accept 0 -30 +expect 0 1005309.6491 +roundtrip 1 + +accept 1 -30 +expect 87064.5795 1004929.7341 +roundtrip 1 + +accept -1 -30 +expect -87064.5795 1004929.7341 +roundtrip 1 + +accept 0 30 +expect 0 7037167.5440 +roundtrip 1 + +accept 0 -40 +expect 0 0 +roundtrip 1 + +accept 1 -41 +expect 75872.2182 -100965.3718 +roundtrip 1 + +------------------------------------------------------------------------------- operation +proj=tmerc +R=1 ------------------------------------------------------------------------------- direction inverse |