mosaic_clip: Clip Raster Mosaic by Polygons
In pliman: Tools for Plant Image Analysis

mosaic_clip

R Documentation

Clip Raster Mosaic by Polygons

Description

Quickly partition a large raster mosaic into individual tiles using a polygon layer. Each tile is clipped by either the polygon's bounding box or (optionally) the exact feature geometry, and written to disk as a separate GeoTIFF named by the feature's unique_id.

Usage

mosaic_clip(
  mosaic,
  shapefile,
  unique_id = "unique_id",
  out_dir = NULL,
  overwrite = TRUE,
  verbose = TRUE,
  exact = FALSE,
  parallel = FALSE,
  workers = NULL
)

Arguments

`mosaic`	A terra::SpatRaster object or a file path pointing to a raster. In-memory rasters are first written to a temporary GeoTIFF.
`shapefile`	An sf::sf, terra::SpatVector, or path to a vector file. Must contain a column named `unique_id` for naming each output tile.
`unique_id`	A column present in `shapefile` that uniquely identifies the plots to be clipped.
`out_dir`	Directory where clipped rasters will be saved. Defaults to the current working directory. Created recursively if it does not exist.
`overwrite`	Logical; if `TRUE` (the default), existing files in `out_dir` with the same name will be overwritten.
`verbose`	Logical; if `TRUE` (default), progress bars and status messages will be shown.
`exact`	Logical; if `FALSE` (default), tiles are cropped by each feature's bounding box. If `TRUE`, the function extracts each polygon as a cutline for an exact crop (slower, but shape-accurate).
`parallel`	Logical; if `TRUE` (default), processing is parallelized using `mirai`. Set to `FALSE` for purely sequential execution.
`workers`	Integer; number of parallel daemons to launch when `parallel = TRUE`. Defaults to 70% of available cores.

Details

Clip a Raster Mosaic by Polygons

This function wraps GDAL's warp utility for efficient raster clipping. When parallel = TRUE, it will spawn multiple workers via mirai and process tiles in batches. Use exact = TRUE to clip to the true polygon shape (at some extra cost), or leave exact = FALSE for a faster bounding-box crop.