hydSpatRaster: Initialize a 'SpatRaster' for the flood-functions

In hydflood: Flood Extents and Duration along the Rivers Elbe and Rhine

Initialize a SpatRaster for the flood-functions

Description

To initialize an object of class SpatRaster with layers dem and csa this function should be used. It checks all the required input data, downloads missing data automatically, clips and returns the final object, prepared for the flood() functions (flood1, flood2 and flood3).

Usage

hydSpatRaster(filename_dem = "", filename_csa = "", ext, crs, ...)

Arguments

filename_dem	an optional argument of length 1 with type character specifying a filename of a digital elevation model raster dataset. If the file exists it is imported via rast and used to build the SpatRaster, potentially cropped by argument ext. If the dem file does not exist, data are downloaded automatically and exported using writeRaster and can be reused to accelerate later computations. An existing dataset must be either in the coordinate reference system (crs) 'ETRS 1989 UTM 32N' (epsg: 25832) for the River Rhine or 'ETRS 1989 UTM 33N' (epsg: 25833) for the River Elbe. It must also overlap with the active floodplains (sf.afe or sf.afr) of the river selected through the crs. If argument filename_csa is specified and exists too, the coordinate reference system (crs), extent (ext) and resolution (res) of both raster datasets must match. Supported file types depend on available GDAL raster drivers.
filename_csa	an optional argument of length 1 with type character specifying a filename of a cross section area raster dataset. If the file exists it is imported via rast and used to build the SpatRaster, potentially cropped by argument ext. If the csa file does not exist, data are downloaded automatically and exported using writeRaster and can be reused to accelerate later computations. An existing dataset must be either in the coordinate reference system (crs) 'ETRS 1989 UTM 32N' (epsg: 25832) for the River Rhine or 'ETRS 1989 UTM 33N' (epsg: 25833) for the River Elbe. It must also overlap with the active floodplains (sf.afe or sf.afr) of the river selected through the crs and be in the possible range of station_int values: Elbe (m 0 - 585700), Rhine (m 336200 - 865700). If argument filename_dem is specified too, coordinate reference system (crs), extent (ext) and resolution (res) of both raster datasets must match. Supported file types depend on available GDAL raster drivers.
ext	optional argument of type SpatExtent. If neither filename_dem nor filename_csa are specified, ext is required to download the respective data and generate temporary dem and csa datasets. If either filename_dem or filename_csa or both are specified, ext must be within the extent of provided raster layers. Then it is used to crop the supplied data.
crs	optional argument of type crs or crs. If neither filename_dem nor filename_csa are specified, crs is used to select the respective river (Elbe: 'ETRS 1989 UTM 33N' (epsg: 25833); Rhine: 'ETRS 1989 UTM 32N' (epsg: 25832)) and crop downloaded dem and csa by the given ext. If either filename_dem or filename_csa or both are specified, crs must match their coordinate reference systems; otherwise an error is returned.
...	additional parameters passed to writeRaster.

Details

Since the underlying tiled digital elevation models (dem) are rather large datasets hydflood provides options to permanentely cache these datasets. options("hydflood.datadir" = tempdir()) is the default. To modify the location of your raster cache to your needs set the respective options() prior to loading the package, e.g. options("hydflood.datadir" = "~/.hydflood");library(hydflood). The location can also be determined through the environmental variable hydflood_datadir.

Since downloads of large individual datasets might cause timeouts, it is recommended to increase options("timeout").

Value

SpatRaster object containing digital elevation (dem) and cross section area (csa) raster layers.

References

\insertRef

wsv_dgmw_2016hydflood

\insertRef

brockmann_auswertung_2008hydflood

\insertRef

brockmann_produktblatt_2012hydflood

\insertRef

brockmann_digitales_2008hydflood

\insertRef

smile_consult_gmbh_dgm-w_2011hydflood

\insertRef

fugro-hgn_gmbh_aufbau_2011hydflood

\insertRef

arge_vermessung_schmid_-_inphoris_aufbau_2012hydflood

\insertRef

weber_dgms_2020hydflood

\insertRef

weber_dgm_elbe_2020hydflood

\insertRef

weber_dgm_rhine_2020hydflood

\insertRef

bundesanstalt_fur_gewasserkunde_flys_2016hydflood

\insertRef

brunotte_flussauen_data_2009hydflood

See Also

SpatRaster-class, rast, writeRaster, flood1, flood2, flood3, sf.afe, sf.afr

Examples

  options("hydflood.datadir" = tempdir())
  options("timeout" = 200)
  library(hydflood)
  
  e <- ext(436500, 438000, 5415000, 5416500)
  c <- st_crs("EPSG:25832")
  
  r <- hydSpatRaster(ext = e, crs = c)
  r

hydflood documentation built on April 4, 2025, 3:42 a.m.