Type:	Package
Title:	Copernicus Digital Elevation Models
Version:	1.0.5
Date:	2024-12-09
URL:	https://github.com/mlampros/CopernicusDEM
Description:	Copernicus Digital Elevation Model datasets (DEM) of 90 and 30 meters resolution using the 'awscli' command line tool. The Copernicus (DEM) is included in the Registry of Open Data on 'AWS (Amazon Web Services)' and represents the surface of the Earth including buildings, infrastructure and vegetation.
License:	GPL-3
Copyright:	inst/COPYRIGHTS.pdf
Encoding:	UTF-8
SystemRequirements:	awscli: apt install -y awscli (deb), aws-configure: aws configure (deb)
Depends:	R(≥ 3.5)
Imports:	glue, sf, utils, doParallel, foreach
RoxygenNote:	7.3.0
Suggests:	rmarkdown, knitr, data.table, fitbitViz, mapview, terra
VignetteBuilder:	knitr
NeedsCompilation:	no
Packaged:	2024-12-09 12:32:34 UTC; lampros
Author:	Lampros Mouselimis [aut, cre]
Maintainer:	Lampros Mouselimis <mouselimislampros@gmail.com>
Repository:	CRAN
Date/Publication:	2024-12-09 13:40:18 UTC

Download the elevation .tif files that intersect either with an input sf (simple features) object or with a .geojson file

Description

Download the elevation .tif files that intersect either with an input sf (simple features) object or with a .geojson file

Usage

aoi_geom_save_tif_matches(
  sf_or_file,
  dir_save_tifs,
  resolution = 90,
  crs_value = 4326,
  threads = parallel::detectCores(),
  verbose = FALSE
)

Arguments

Details

Download Computation time: Based on a sample of 90 meter resolution images that I downloaded each file was approximately 5 MB which means in total I had to download 130 GB of data (in case I intended to download all 20.000 files of the land areas worldwide). Therefore it is wise to download data based on the intersection of the input Area of Interest (AOI) and an existing tile-grid of the Digital Elevation Model (DEM)

The 30 meter resolution .tif images are bigger in size but visually better (approximate image size of 1.7 MB compared to 13 MB). The time to download 90 meter resolution data is approximately 20 seconds compared to 1 minute and 10 seconds of the 30 meter resolution data (for a sample use case)

Value

a list object of length 2

References

https://registry.opendata.aws/copernicus-dem/

https://copernicus-dem-30m.s3.amazonaws.com/readme.html

https://spacedata.copernicus.eu/en/web/guest/collections/copernicus-digital-elevation-model/

Examples

## Not run: 

#.......................................
# create a directory to save the .tif
# files based on a Well Known Text (WKT)
# of a sample Area of Interest (AOI)
#.......................................

DIR_SAVE = file.path(Sys.getenv('HOME'), 'DIR_SAVE_DEM')
if (!dir.exists(DIR_SAVE)) dir.create(DIR_SAVE)

WKT='POLYGON((61.5234 27.0591, 63.6328 27.0591, 63.6328 28.1495, 61.5234 28.1495, 61.5234 27.0591))'

sf_obj = sf::st_as_sfc(WKT, crs = 4326)
sf_obj = sf::st_make_valid(sf_obj)

#.............
# 90 meter DEM
#.............

save_matches = CopernicusDEM::aoi_geom_save_tif_matches(sf_or_file = sf_obj,
                                                        dir_save_tifs = DIR_SAVE,
                                                        resolution = 90,
                                                        crs_value = 4326,
                                                        threads = parallel::detectCores(),
                                                        verbose = TRUE)

#.............
# 30 meter DEM
#.............

save_matches = CopernicusDEM::aoi_geom_save_tif_matches(sf_or_file = sf_obj,
                                                        dir_save_tifs = DIR_SAVE,
                                                        resolution = 30,
                                                        crs_value = 4326,
                                                        threads = parallel::detectCores(),
                                                        verbose = TRUE)

## End(Not run)

elapsed time in hours & minutes & seconds

Description

elapsed time in hours & minutes & seconds

Usage

compute_elapsed_time(time_start)

Arguments

Value

It does not return a value but only prints the time in form of a character string in the R session

Create a Virtual Raster (VRT) file from .tif files

Description

Create a Virtual Raster (VRT) file from .tif files

Usage

create_VRT_from_dir(
  dir_tifs,
  output_path_VRT,
  file_extension = ".tif",
  verbose = FALSE
)

Arguments

Value

it doesn't return an object but it saves the output to a file

Examples

## Not run: 

#.........................................................
# create a directory to save the .tif files and a
# Well Known Text (WKT) of a sample Area of Interest (AOI)
#.........................................................

DIR_SAVE = file.path(Sys.getenv('HOME'), 'DIR_SAVE_DEM')
if (!dir.exists(DIR_SAVE)) dir.create(DIR_SAVE)

WKT='POLYGON((61.5234 27.0591, 63.6328 27.0591, 63.6328 28.1495, 61.5234 28.1495, 61.5234 27.0591))'

sf_obj = sf::st_as_sfc(WKT, crs = 4326)
sf_obj = sf::st_make_valid(sf_obj)

#......................
# download 90 meter DEM
#......................

save_matches = CopernicusDEM::aoi_geom_save_tif_matches(sf_or_file = sf_obj,
                                                        dir_save_tifs = DIR_SAVE,
                                                        resolution = 90,
                                                        crs_value = 4326,
                                                        threads = parallel::detectCores(),
                                                        verbose = TRUE)

#........................................
# create a Virtual Raster (VRT) file from
# the 90 meter downloaded .tif files
#........................................

VRT_out = as.character(glue::glue("{DIR_SAVE}.vrt"))

res_vrt = CopernicusDEM::create_VRT_from_dir(dir_tifs = DIR_SAVE,
                                             output_path_VRT = VRT_out,
                                             verbose = TRUE)

#......................................................
# load the saved VRT file as raster (which might
# consist of multiple files, i.e. a mosaic) and plot it
#......................................................

rst = raster::raster(VRT_out)
sp::plot(rst)


## End(Not run)

inner function of 'compute_elapsed_time'

Description

inner function of 'compute_elapsed_time'

Usage

inner_elapsed_time(secs, estimated = FALSE)

Arguments

Value

a character string showing the estimated or elapsed time