fastfocal

fastfocal: Fast Multi-scale Raster Extraction and Moving Window Analysis with Fast Fourier Transform (FFT) in R

fastfocal provides high-performance, flexible raster smoothing and extraction functions in R using moving windows, buffer-based zones, and an auto-switching FFT backend for large kernels. It supports multiple focal statistics and allows users to work at multiple spatial scales with ease.

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Installation

You can install the stable version via CRAN:

install.packages("fastfocal")

You can install the development version from GitHub:

# install.packages("remotes")
remotes::install_github("hoyiwan/fastfocal")

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Overview

This package includes:

• fastfocal() — fast moving-window smoothing with support for mean, sum, min, max, sd, and median
• fastextract() — fast extraction of raster values at point or buffer locations
• fastfocal_weights() — utility for generating spatial weight matrices (circular, Gaussian, etc.)
• Auto-switch backend to FFT for large windows to improve performance
  • FFT backend currently supports sum and mean; other statistics use the terra backend
• Native support for terra::SpatRaster and terra::SpatVector objects

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Example Usage

library(fastfocal)
library(terra)

# Create a dummy raster
r <- rast(nrows = 100, ncols = 100, xmin = 0, xmax = 3000, ymin = 0, ymax = 3000)
values(r) <- runif(ncell(r))

# Apply fast focal smoothing with circular window of radius 300
smoothed <- fastfocal(r, d = 300, w = "circle", fun = "mean")

# Plot the result
plot(smoothed)

Weighted extraction at points:

# Create SpatVector of points
pts <- vect(data.frame(x = c(500, 1500), y = c(500, 2500)), geom = c("x", "y"), crs = crs(r))

# Extract raster values in 500 m buffers around points
result <- fastextract(r, pts, d = 500, fun = "mean")
print(result)

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Vignettes

• Introduction (Index)
• Benchmark: fastfocal vs terra::focal

You can also access them from R using:

vignette("index", package = "fastfocal")

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License

This package is licensed under the MIT License (see the LICENSE file).

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Citation

If you use fastfocal in published work, please cite it as:

Ho Yi Wan (2025). fastfocal: Fast Multi-scale Raster Extraction and Moving Window Analysis with Fast Fourier Transform (FFT) in R. Version v0.1.4. Zenodo. https://doi.org/10.5281/zenodo.17074691

Or use the BibTeX entry:

@software{wan_fastfocal_2025,
  author       = {Ho Yi Wan},
  title        = {fastfocal: Fast Multi-scale Raster Extraction and Moving Window Analysis with Fast Fourier Transform (FFT) in R},
  version      = {v0.1.4},
  year         = {2025},
  publisher    = {Zenodo},
  doi          = {10.5281/zenodo.17074691},
  url          = {https://doi.org/10.5281/zenodo.17074691}
}

You can also run:

citation("fastfocal")

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Author

Ho Yi Wan
hoyiwan@gmail.com

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Purpose

Built to support large-scale ecological analysis, high-performance raster processing, and reproducible landscape research workflows.