diff options
Diffstat (limited to 'src/grids.cpp')
| -rw-r--r-- | src/grids.cpp | 44 |
1 files changed, 28 insertions, 16 deletions
diff --git a/src/grids.cpp b/src/grids.cpp index 24fcfe83..68bf8600 100644 --- a/src/grids.cpp +++ b/src/grids.cpp @@ -1837,17 +1837,20 @@ std::unique_ptr<NTv2GridSet> NTv2GridSet::open(PJ_CONTEXT *ctx, pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID); return nullptr; } - if (memcmp(header + 56, "SECONDS", 7) != 0) { + + constexpr int OFFSET_GS_TYPE = 56; + if (memcmp(header + OFFSET_GS_TYPE, "SECONDS", 7) != 0) { pj_log(ctx, PJ_LOG_ERROR, "Only GS_TYPE=SECONDS is supported"); pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID); return nullptr; } const bool must_swap = (header[8] == 11) ? !IS_LSB : IS_LSB; + constexpr int OFFSET_NUM_SUBFILES = 8 + 32; if (must_swap) { // swap_words( header+8, 4, 1 ); // swap_words( header+8+16, 4, 1 ); - swap_words(header + 8 + 32, 4, 1); + swap_words(header + OFFSET_NUM_SUBFILES, 4, 1); // swap_words( header+8+7*16, 8, 1 ); // swap_words( header+8+8*16, 8, 1 ); // swap_words( header+8+9*16, 8, 1 ); @@ -1858,7 +1861,7 @@ std::unique_ptr<NTv2GridSet> NTv2GridSet::open(PJ_CONTEXT *ctx, /* Get the subfile count out ... all we really use for now. */ /* -------------------------------------------------------------------- */ unsigned int num_subfiles; - memcpy(&num_subfiles, header + 8 + 32, 4); + memcpy(&num_subfiles, header + OFFSET_NUM_SUBFILES, 4); std::map<std::string, NTv2Grid *> mapGrids; @@ -1878,25 +1881,31 @@ std::unique_ptr<NTv2GridSet> NTv2GridSet::open(PJ_CONTEXT *ctx, } // Byte swap interesting fields if needed. + constexpr int OFFSET_GS_COUNT = 8 + 16 * 10; + constexpr int OFFSET_SOUTH_LAT = 8 + 16 * 4; if (must_swap) { - swap_words(header + 8 + 16 * 4, sizeof(double), 6); - swap_words(header + 8 + 16 * 10, sizeof(int), 1); + // 6 double values: southLat, northLat, eastLon, westLon, resLat, + // resLon + swap_words(header + OFFSET_SOUTH_LAT, sizeof(double), 6); + swap_words(header + OFFSET_GS_COUNT, sizeof(int), 1); } std::string gridName; gridName.append(header + 8, 8); ExtentAndRes extent; - extent.westLon = - -to_double(header + 7 * 16 + 8) * DEG_TO_RAD / 3600.0; /* W_LONG */ - extent.southLat = - to_double(header + 4 * 16 + 8) * DEG_TO_RAD / 3600.0; /* S_LAT */ - extent.eastLon = - -to_double(header + 6 * 16 + 8) * DEG_TO_RAD / 3600.0; /* E_LONG */ - extent.northLat = - to_double(header + 5 * 16 + 8) * DEG_TO_RAD / 3600.0; /* N_LAT */ - extent.resLon = to_double(header + 9 * 16 + 8) * DEG_TO_RAD / 3600.0; - extent.resLat = to_double(header + 8 * 16 + 8) * DEG_TO_RAD / 3600.0; + extent.southLat = to_double(header + OFFSET_SOUTH_LAT) * DEG_TO_RAD / + 3600.0; /* S_LAT */ + extent.northLat = to_double(header + OFFSET_SOUTH_LAT + 16) * + DEG_TO_RAD / 3600.0; /* N_LAT */ + extent.eastLon = -to_double(header + OFFSET_SOUTH_LAT + 16 * 2) * + DEG_TO_RAD / 3600.0; /* E_LONG */ + extent.westLon = -to_double(header + OFFSET_SOUTH_LAT + 16 * 3) * + DEG_TO_RAD / 3600.0; /* W_LONG */ + extent.resLat = + to_double(header + OFFSET_SOUTH_LAT + 16 * 4) * DEG_TO_RAD / 3600.0; + extent.resLon = + to_double(header + OFFSET_SOUTH_LAT + 16 * 5) * DEG_TO_RAD / 3600.0; if (!(fabs(extent.westLon) <= 4 * M_PI && fabs(extent.eastLon) <= 4 * M_PI && @@ -1923,7 +1932,7 @@ std::unique_ptr<NTv2GridSet> NTv2GridSet::open(PJ_CONTEXT *ctx, extent.northLat * RAD_TO_DEG); unsigned int gs_count; - memcpy(&gs_count, header + 8 + 16 * 10, 4); + memcpy(&gs_count, header + OFFSET_GS_COUNT, 4); if (gs_count / columns != static_cast<unsigned>(rows)) { pj_log(ctx, PJ_LOG_ERROR, "GS_COUNT(%u) does not match expected cells (%dx%d)", @@ -2845,6 +2854,7 @@ ListOfHGrids pj_hgrid_init(PJ *P, const char *gridkey) { typedef struct { pj_int32 lam, phi; } ILP; +// Apply bilinear interpolation for horizontal shift grids static PJ_LP pj_hgrid_interpolate(PJ_LP t, const HorizontalShiftGrid *grid, bool compensateNTConvention) { PJ_LP val, frct; @@ -3283,6 +3293,8 @@ const GenericShiftGrid *pj_find_generic_grid(const ListOfGenericGrids &grids, // --------------------------------------------------------------------------- +// Used by +proj=deformation and +proj=xyzgridshift to do bilinear interpolation +// on 3 sample values per node. bool pj_bilinear_interpolation_three_samples(const GenericShiftGrid *grid, const PJ_LP &lp, int idx1, int idx2, int idx3, double &v1, |