An easy way to use gdal warp in R

super handy warper but limited in that returns in memory SpatRast. May cause issues when creating a raster > memory. Also not clear how to implement the cutline feature.

Usage

ezwarp(
  x,
  y,
  res,
  bands = NULL,
  resample = "bilinear",
  cutline = NULL,
  crop_to_cutline = FALSE,
  nodata = NULL,
  out_class = c("SpatRaster", "stars", "path", "rayshader", "vector"),
  filename = NULL,
  overwrite = TRUE,
  options = "",
  compression = "DEFLATE",
  engine = c("vapour", "sf"),
  ...
)

Arguments

x: a list or vector of raster source(s) or SpatRaster(s)
y: a raster source, SpatRaster, sf, or sfc
res: numeric. the resolution of the output SpatRaster.
bands: numeric which bands to use from the source. Only used if engine="vapour"
resample: resampling method. default is bilinear, see details.
cutline: an sf, sfc, SpatVector or ogr-readable spatial vector source to mask the output raster. see -cutline argument in gdalwarp
crop_to_cutline: logical. If TRUE, then the output will be cropped to the limits of the mask given in cutline.
nodata: Numeric. No data value to be used for output.
out_class: default is "SpatRaster". Can be either "SpatRaster", "stars", "path", "rayshader", or "vector".
filename: the filepath for the out raster. if given and "vapour" is used for the engine, then the output SpatRaster/stars object will have a source. If NULL then an in memory raster is returned. If the sf engine is used and filename is NULL then a tempfile is used.
overwrite: logical - should a file be overwritten.
options: gdal options.
compression: default is "DEFLATE". character describing tif compression e.g. "LZW"
engine: either "vapour" or "sf". choose which warper to use. Only vapour supports in memory raster creation.
...: Additional args passed to vapour::vapour_warp_raster. Might be removed.

Value

one of the following as defined in out_class: 'SpatRaster', 'stars','matrix', 'vector'

Details

When selecting the resample method, choose from the following options: 'bilinear' (the default), 'near', 'cubic', 'cubicspline', 'lanczos', 'average', 'mode', 'max', 'min', 'med', 'q1', 'q3', 'sum'. For details on these methods see: https://gdal.org/programs/gdalwarp.html. If raster source is categorical make sure to use 'nearest'.

If "rayshader" is used for out_class, then a matrix is returned if only one band is targeted. If multiple bands are targeted, then a n-dimensional array is returned. The matrix is returned oriented North is up.

If "vector" is used for out_class, a vector is returned for a single band target, and a list of vectors is returned for a multiband target.

If "path" is used for out_class, a path to the output raster is returned.

Examples

f <- system.file("ex/elev.tif", package = "terra")
r.terra <- terra::rast(f)

ezwarp(f, f, res = 1e-4)
#> class       : SpatRaster 
#> dimensions  : 7501, 7918, 1  (nrow, ncol, nlyr)
#> resolution  : 1e-04, 1e-04  (x, y)
#> extent      : 5.7416, 6.5334, 49.4416, 50.1917  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326) 
#> source(s)   : memory
#> name        : Band1 
#> min value   :   141 
#> max value   :   547 

ezwarp(r.terra, f, res = 1e-4, engine = "sf", out_class = "stars")
#> stars object with 2 dimensions and 1 attribute
#> attribute(s), summary of first 1e+05 cells:
#>                       Min. 1st Qu. Median Mean 3rd Qu. Max.  NA's
#> file198216840b6e.tif    NA      NA     NA  NaN      NA   NA 1e+05
#> dimension(s):
#>   from   to  offset  delta refsys point x/y
#> x    1 7918  5.7416  1e-04 WGS 84 FALSE [x]
#> y    1 7501 50.1917 -1e-04 WGS 84 FALSE [y]

v <- ezwarp(r.terra, f, res = 1e-4, out_class = "vector")[[1]]
hist(v)