edu.ucar.opensky::technotes:514 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T03:43:27.290154 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7862fv1 Two-dimensional kernel smoothing: Using the R package smoothie 2013-07-01T00:00:00Z publication https://n2t.org/ark:/85065/d7862fv1 https://doi.org/10.5065/D61834G2 Gilleland, Eric author UCAR/NCAR - Library publisher Applying a kernel smoother to a two-dimensional field can be a laborious and computationally expensive process if carried out in the most obvious fashion (applying a double loop). One might consider the alternative of stacking a location matrix and applying the kernel smoother in a more efficient way (e.g., through the R function aggregate). However, for large grids this may not be practical or even possible. The methods have the advantage of being able to handle missing values and edges (with fewer neighbors) directly, but if these are not pivotal concerns, the convolution theorem along with the fast Fourier transform (FFT) provides a very speedy alternative. The R package smoothie provides functionality for smoothing a two-dimensional field (or image) using the convolution theorem and FFT, and is used extensively in the spatial weather forecast verification package, Spatial Vx. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Statistical applications theme U.S. National Aeronautics and Space Administration Global Change Master Directory GCMD 2021-09-17 revision 11.2 NASA Global Change Master Directory originator Valids List: Science and Services Keywords Copyright Author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation