How are grids resampled in the IDV?
A. The IDV uses two methods for resampling data – weighted average and nearest neighbor. These are the default sampling mode for VisAD which the IDV is based on. For any grid, the samples are organized in a topology, which may be triangles (Irregular2D), squares (Gridded2D), tetrahedra (Irregular3D) or cubes (Gridded3D). For target points the system finds which topology element contains the target. For nearest neighbor, it gets the values at the vertex of that containing topology element closest to the target point. For weighted average, its computes a weighted average of all vertices of that containing topology element, where the weights are bilinear in 2-D and trilinear in 3-D.
