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Diffstat (limited to 'src/projections/times.cpp')
| -rw-r--r-- | src/projections/times.cpp | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/projections/times.cpp b/src/projections/times.cpp new file mode 100644 index 00000000..e8b4499f --- /dev/null +++ b/src/projections/times.cpp @@ -0,0 +1,79 @@ +/****************************************************************************** + * Project: PROJ.4 + * Purpose: Implementation of the Times projection. + * Author: Kristian Evers <kristianevers@gmail.com> + * + ****************************************************************************** + * Copyright (c) 2016, Kristian Evers + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included + * in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + ***************************************************************************** + * Based on describtion of the Times Projection in + * + * Flattening the Earth, Snyder, J.P., 1993, p.213-214. + *****************************************************************************/ + +#define PJ_LIB__ + +#include <math.h> + +#include "projects.h" + +PROJ_HEAD(times, "Times") "\n\tCyl, Sph"; + +static XY s_forward (LP lp, PJ *P) { /* Spheroidal, forward */ + double T, S, S2; + XY xy = {0.0,0.0}; + (void) P; + + T = tan(lp.phi/2.0); + S = sin(M_FORTPI * T); + S2 = S*S; + + xy.x = lp.lam * (0.74482 - 0.34588*S2); + xy.y = 1.70711 * T; + + return xy; +} + + +static LP s_inverse (XY xy, PJ *P) { /* Spheroidal, inverse */ + double T, S, S2; + LP lp = {0.0,0.0}; + (void) P; + + T = xy.y / 1.70711; + S = sin(M_FORTPI * T); + S2 = S*S; + + lp.lam = xy.x / (0.74482 - 0.34588 * S2); + lp.phi = 2 * atan(T); + + return lp; +} + + +PJ *PROJECTION(times) { + P->es = 0.0; + + P->inv = s_inverse; + P->fwd = s_forward; + + return P; +} |
