diff options
Diffstat (limited to 'src/grids.cpp')
| -rw-r--r-- | src/grids.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/grids.cpp b/src/grids.cpp index a5d9da8e..3284bf02 100644 --- a/src/grids.cpp +++ b/src/grids.cpp @@ -3381,7 +3381,12 @@ bool pj_bilinear_interpolation_three_samples( return false; } + // From a input location lp, determine the grid cell into which it falls, + // by identifying the lower-left x,y of it (ix, iy), and the upper-right + // (ix2, iy2) + double grid_x = (lp.lam - extent.west) / extent.resX; + // Special case for grids with world extent, and dealing with wrap-around if (lp.lam < extent.west) { grid_x = (lp.lam + 2 * M_PI - extent.west) / extent.resX; } else if (lp.lam > extent.east) { @@ -3417,6 +3422,7 @@ bool pj_bilinear_interpolation_three_samples( return false; } + // Bilinear interpolation double frct_lam = grid_x - ix; double frct_phi = grid_y - iy; double m10 = frct_lam; |