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| author | Even Rouault <even.rouault@spatialys.com> | 2018-12-19 13:00:37 +0100 |
|---|---|---|
| committer | Even Rouault <even.rouault@spatialys.com> | 2018-12-26 10:08:55 +0100 |
| commit | df574ae332d57f556fd56314883b3354cab1d0ff (patch) | |
| tree | 63a68d40d7ed7932d6329d9c7baa340bb6294f7f /src/transformations/deformation.cpp | |
| parent | e6de172371ea203f6393d745641d66c82b5b13e2 (diff) | |
| download | PROJ-df574ae332d57f556fd56314883b3354cab1d0ff.tar.gz PROJ-df574ae332d57f556fd56314883b3354cab1d0ff.zip | |
cpp conversion: remove useless pj_, PJ_ and proj_ filename prefixes
Diffstat (limited to 'src/transformations/deformation.cpp')
| -rw-r--r-- | src/transformations/deformation.cpp | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/src/transformations/deformation.cpp b/src/transformations/deformation.cpp new file mode 100644 index 00000000..6c30f21c --- /dev/null +++ b/src/transformations/deformation.cpp @@ -0,0 +1,325 @@ +/*********************************************************************** + + Kinematic datum shifting utilizing a deformation model + + Kristian Evers, 2017-10-29 + +************************************************************************ + +Perform datum shifts by means of a deformation/velocity model. + + X_out = X_in + (T_ct - T_obs)*DX + Y_out = Y_in + (T_ct - T_obs)*DY + Z_out = Z_in + (T_ct - T_obs)*DZ + + +The deformation operation takes cartesian coordinates as input and +returns cartesian coordinates as well. + +Corrections in the gridded model are in east, north, up (ENU) space. +Hence the input coordinates needs to be converted to ENU-space when +searching for corrections in the grid. The corrections are then converted +to cartesian XYZ-space and applied to the input coordinates (also in +cartesian space). + +A full deformation model is described by two grids, one for the horizontal +components and one for the vertical component. The horizontal grid is +stored in CTable/CTable2 and the vertical grid is stored in the GTX +format. The NTv2 format should not be used for this purpose since grid- +values are scaled upon reading. Both grids are expected to contain +grid-values in units of mm/year in ENU-space. + +************************************************************************ +* Copyright (c) 2017, 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. +* +***********************************************************************/ +#define PJ_LIB__ +#include <errno.h> +#include "proj.h" +#include "proj_internal.h" +#include "proj_math.h" +#include "projects.h" + +PROJ_HEAD(deformation, "Kinematic grid shift"); + +#define TOL 1e-8 +#define MAX_ITERATIONS 10 + +namespace { // anonymous namespace +struct pj_opaque { + double t_obs; + double t_epoch; + PJ *cart; +}; +} // anonymous namespace + +/********************************************************************************/ +static XYZ get_grid_shift(PJ* P, XYZ cartesian) { +/******************************************************************************** + Read correction values from grid. The cartesian input coordinates are + converted to geodetic coordinates in order look up the correction values + in the grid. Once the grid corrections are read we need to convert them + from ENU-space to cartesian XYZ-space. ENU -> XYZ formula described in: + + Nørbech, T., et al, 2003(?), "Transformation from a Common Nordic Reference + Frame to ETRS89 in Denmark, Finland, Norway, and Sweden – status report" + +********************************************************************************/ + PJ_COORD geodetic, shift, temp; + double sp, cp, sl, cl; + int previous_errno = proj_errno_reset(P); + + /* cartesian to geodetic */ + geodetic.lpz = pj_inv3d(cartesian, static_cast<struct pj_opaque*>(P->opaque)->cart); + + /* look up correction values in grids */ + shift.lp = proj_hgrid_value(P, geodetic.lp); + shift.enu.u = proj_vgrid_value(P, geodetic.lp); + + if (proj_errno(P) == PJD_ERR_GRID_AREA) + proj_log_debug(P, "deformation: coordinate (%.3f, %.3f) outside deformation model", + proj_todeg(geodetic.lp.lam), proj_todeg(geodetic.lp.phi)); + + /* grid values are stored as mm/yr, we need m/yr */ + shift.xyz.x /= 1000; + shift.xyz.y /= 1000; + shift.xyz.z /= 1000; + + /* pre-calc cosines and sines */ + sp = sin(geodetic.lp.phi); + cp = cos(geodetic.lp.phi); + sl = sin(geodetic.lp.lam); + cl = cos(geodetic.lp.lam); + + /* ENU -> XYZ */ + temp.xyz.x = -sp*cl*shift.enu.n - sl*shift.enu.e + cp*cl*shift.enu.u; + temp.xyz.y = -sp*sl*shift.enu.n + cl*shift.enu.e + cp*sl*shift.enu.u; + temp.xyz.z = cp*shift.enu.n + sp*shift.enu.u; + + shift.xyz = temp.xyz; + + proj_errno_restore(P, previous_errno); + + return shift.xyz; +} + +/********************************************************************************/ +static XYZ reverse_shift(PJ *P, XYZ input, double dt) { +/******************************************************************************** + Iteratively determine the reverse grid shift correction values. +*********************************************************************************/ + XYZ out, delta, dif; + double z0; + int i = MAX_ITERATIONS; + + delta = get_grid_shift(P, input); + + /* Store the origial z shift for later application */ + z0 = delta.z; + + /* When iterating to find the best horizontal coordinate we also carry */ + /* along the z-component, since we need it for the cartesian -> geodetic */ + /* conversion. The z-component adjustment is overwritten with z0 after */ + /* the loop has finished. */ + out.x = input.x - dt*delta.x; + out.y = input.y - dt*delta.y; + out.z = input.z + dt*delta.z; + + do { + delta = get_grid_shift(P, out); + + if (delta.x == HUGE_VAL) + break; + + dif.x = out.x + dt*delta.x - input.x; + dif.y = out.y + dt*delta.y - input.y; + dif.z = out.z - dt*delta.z - input.z; + out.x += dif.x; + out.y += dif.y; + out.z += dif.z; + + } while ( --i && hypot(dif.x, dif.y) > TOL ); + + out.z = input.z - dt*z0; + + return out; +} + +static XYZ forward_3d(LPZ lpz, PJ *P) { + struct pj_opaque *Q = (struct pj_opaque *) P->opaque; + PJ_COORD out, in; + XYZ shift; + double dt = 0.0; + in.lpz = lpz; + out = in; + + if (Q->t_obs != HUGE_VAL) { + dt = Q->t_epoch - Q->t_obs; + } else { + out = proj_coord_error(); /* in the 3D case +t_obs must be specified */ + proj_log_debug(P, "deformation: +t_obs must be specified"); + return out.xyz; + } + + shift = get_grid_shift(P, in.xyz); + + out.xyz.x += dt * shift.x; + out.xyz.y += dt * shift.y; + out.xyz.z += dt * shift.z; + + return out.xyz; +} + + +static PJ_COORD forward_4d(PJ_COORD in, PJ *P) { + struct pj_opaque *Q = (struct pj_opaque *) P->opaque; + double dt; + XYZ shift; + PJ_COORD out = in; + + if (Q->t_obs != HUGE_VAL) { + dt = Q->t_epoch - Q->t_obs; + } else { + dt = Q->t_epoch - in.xyzt.t; + } + + shift = get_grid_shift(P, in.xyz); + + out.xyzt.x += dt*shift.x; + out.xyzt.y += dt*shift.y; + out.xyzt.z += dt*shift.z; + + + return out; +} + + +static LPZ reverse_3d(XYZ in, PJ *P) { + struct pj_opaque *Q = (struct pj_opaque *) P->opaque; + PJ_COORD out; + double dt = 0.0; + out.xyz = in; + + if (Q->t_obs != HUGE_VAL) { + dt = Q->t_epoch - Q->t_obs; + } else { + out = proj_coord_error(); /* in the 3D case +t_obs must be specified */ + proj_log_debug(P, "deformation: +t_obs must be specified"); + return out.lpz; + } + + out.xyz = reverse_shift(P, in, dt); + + return out.lpz; +} + +static PJ_COORD reverse_4d(PJ_COORD in, PJ *P) { + struct pj_opaque *Q = (struct pj_opaque *) P->opaque; + PJ_COORD out = in; + double dt; + + + if (Q->t_obs != HUGE_VAL) { + dt = Q->t_epoch - Q->t_obs; + } else { + dt = Q->t_epoch - in.xyzt.t; + } + + out.xyz = reverse_shift(P, in.xyz, dt); + return out; +} + +static PJ *destructor(PJ *P, int errlev) { + if (nullptr==P) + return nullptr; + + if (nullptr==P->opaque) + return pj_default_destructor (P, errlev); + + if (static_cast<struct pj_opaque*>(P->opaque)->cart) + static_cast<struct pj_opaque*>(P->opaque)->cart->destructor (static_cast<struct pj_opaque*>(P->opaque)->cart, errlev); + + return pj_default_destructor(P, errlev); +} + + +PJ *TRANSFORMATION(deformation,1) { + int has_xy_grids = 0; + int has_z_grids = 0; + struct pj_opaque *Q = static_cast<struct pj_opaque*>(pj_calloc (1, sizeof (struct pj_opaque))); + if (nullptr==Q) + return destructor(P, ENOMEM); + P->opaque = (void *) Q; + + Q->cart = proj_create(P->ctx, "+proj=cart"); + if (Q->cart == nullptr) + return destructor(P, ENOMEM); + + /* inherit ellipsoid definition from P to Q->cart */ + pj_inherit_ellipsoid_def (P, Q->cart); + + has_xy_grids = pj_param(P->ctx, P->params, "txy_grids").i; + has_z_grids = pj_param(P->ctx, P->params, "tz_grids").i; + + /* Build gridlists. Both horizontal and vertical grids are mandatory. */ + if (!has_xy_grids || !has_z_grids) { + proj_log_error(P, "deformation: Both +xy_grids and +z_grids should be specified."); + return destructor(P, PJD_ERR_NO_ARGS ); + } + + proj_hgrid_init(P, "xy_grids"); + if (proj_errno(P)) { + proj_log_error(P, "deformation: could not find requested xy_grid(s)."); + return destructor(P, PJD_ERR_FAILED_TO_LOAD_GRID); + } + + proj_vgrid_init(P, "z_grids"); + if (proj_errno(P)) { + proj_log_error(P, "deformation: could not find requested z_grid(s)."); + return destructor(P, PJD_ERR_FAILED_TO_LOAD_GRID); + } + + Q->t_obs = HUGE_VAL; + if (pj_param(P->ctx, P->params, "tt_obs").i) { + Q->t_obs = pj_param(P->ctx, P->params, "dt_obs").f; + } + + if (pj_param(P->ctx, P->params, "tt_epoch").i) { + Q->t_epoch = pj_param(P->ctx, P->params, "dt_epoch").f; + } else { + proj_log_error(P, "deformation: +t_epoch parameter missing."); + return destructor(P, PJD_ERR_MISSING_ARGS); + } + + P->fwd4d = forward_4d; + P->inv4d = reverse_4d; + P->fwd3d = forward_3d; + P->inv3d = reverse_3d; + P->fwd = nullptr; + P->inv = nullptr; + + P->left = PJ_IO_UNITS_CARTESIAN; + P->right = PJ_IO_UNITS_CARTESIAN; + P->destructor = destructor; + + return P; +} + |
