Warp a remote GeoTIFF / COG (a streaming sibling of gdalraster::warp)

A near drop-in for gdalraster::warp() that reads its source(s) remotely. The call shape is the same – src, dst, t_srs, and a raw gdalwarp argument vector in cl_arg – but instead of letting GDAL pull the source over /vsicurl, cptkirk works out which pixels the request touches and streams just those tiles over the Rust async-tiff reader (at the appropriate overview level), stages them in /vsimem, then hands the warp to GDAL. Output is identical to gdalraster::warp() of the same source.

Usage

warp_remote(
  src,
  dst,
  t_srs = "",
  cl_arg = NULL,
  quiet = TRUE,
  overview = NULL,
  margin = 8L,
  io_concurrency = 16L,
  max_bytes = NULL,
  sanitise = TRUE
)

Arguments

src

Path/URL to a source GeoTIFF / COG, a cog_source() handle, or a character vector of several sources to mosaic. A cog_source() reuses its already-open handle, skipping the metadata re-read.

dst

Output filename (a regular path, /vsimem/, or anything GDAL can write). The format is inferred by GDAL or set with -of in cl_arg.

t_srs

Target SRS (e.g. "EPSG:3857"), as in gdalraster::warp(). "" (the default) or NULL means no reprojection (source CRS).

cl_arg

Character vector of raw gdalwarp flags, forwarded verbatim to gdalraster::warp() (e.g. c("-te", "0", "0", "100", "100", "-tr", "10", "10", "-r", "bilinear")). cptkirk parses -te/-te_srs/-tr/-ts from it purely to size the fetch.

quiet

If TRUE (default), the GDAL warp runs without a progress callback. Unlike gdalraster::warp() this defaults to TRUE: a progress callback invoked from GDAL's worker threads (e.g. with -multi) can crash the R session.

overview

Force a 1-based IFD/overview level instead of auto-selecting from the output resolution. 1 = full resolution.

margin

Source-pixel margin added around the computed window to cover the resampling kernel and reprojection slop (default 8).

io_concurrency

Number of concurrent tile reads – the width of the single global fetch pool shared across all source tiles (default 16).

max_bytes

Safety ceiling (bytes) on the staged in-memory window. NULL (default) uses ~1/3 of system RAM.

sanitise

If TRUE (default), validate cl_arg (and t_srs) against a tiny metadata-derived stand-in before fetching, so a bad CRS, resampling method, creation option or unknown flag fails in milliseconds instead of after a remote read. Set FALSE to skip the check.

Value

The dst path, invisibly.

Details

This is the faithful low-level interface: it adds none of cptkirk's performance opinions and forwards cl_arg to GDAL verbatim. For the recommended, batteries-included helper (named te/tr/ts/r/bands arguments, multi-threading, SKIP_NOSOURCE, band-subset streaming, ...) use ck_warp().

See also

ck_warp() for the recommended helper with named arguments and cptkirk's defaults.