projectRasterDWD {rdwd}

project DWD raster data

Description

Set projection and extent for DWD raster data. Optionally (and per default) also reprojects to latlon data.

WARNING: reprojection to latlon changes values slightly. For the tested RX product, this change is significant, see: https://github.com/brry/rdwd/blob/master/misc/ExampleTests/Radartests.pdf
In terra::plot, use range=zlim with the original range if needed.

Usage

projectRasterDWD(
  r,
  proj = "radolan",
  extent = "radolan",
  adjust05 = FALSE,
  targetproj = "ll",
  threads = TRUE,
  quiet = rdwdquiet()
)

Arguments

r

terra raster object

proj

Current projection to be given to r. Can be
- a terra::crs() input,
- NULL to not set proj+extent (but still consider targetproj),
- or a special charstring for internal defaults, namely: "radolan" (readDWD.binary + .asc + .radar), "seasonal" (.raster) or "nc" (.nc).
DEFAULT: "radolan"

extent

Current terra::ext() extent to be given to r. Ignored if proj=NULL. Can be NULL to be ignored, an extent object, a vector with 4 numbers, or "radolan" / "rw" / "seasonal" / "nc" with internal defaults. DEFAULT: "radolan"

adjust05

Logical: Adjust extent by 0.5m to match edges? DEFAULT: FALSE

targetproj

r is reprojected to this terra::crs(). Use NULL to not reproject (i.e. only set proj and extent). DEFAULT: "ll" with internal default for lat-lon.

threads

Use multiple CPU threads for terra::project()? DEFAULT: TRUE (opposite from terra::project)

quiet

Logical: suppress progress messages? DEFAULT: FALSE through rdwdquiet()

Details

The internal defaults are extracted from the Kompositformatbeschreibung at https://www.dwd.de/DE/leistungen/radolan/radolan.html, as provided 2019-04 by Antonia Hengst.
The nc extent was obtained by projecting Germanys bbox to EPSG 3034 (specified in the DWD documentation). Using that as a starting point, I then refined the extent to a visual match, see developmentNotes.R

Value

terra raster object with projection and extent, invisible

Author(s)

Berry Boessenkool, [e-mail], May 2019, June 2023

See Also

plotRadar()
⁠terra::⁠crs / ext / project
readDWD.binary / raster / asc / radar / nc
website raster chapter

Examples

# To be used after readDWD.binary etc