--- title: "elevation-sources" output: rmarkdown::html_vignette vignette: > %\VignetteIndexEntry{elevation-sources} %\VignetteEngine{knitr::rmarkdown} %\VignetteEncoding{UTF-8} --- ```{r, include = FALSE} knitr::opts_chunk$set( collapse = TRUE, comment = "#>" ) ``` whatarelief provides two sources of topography, the first is a global topography and bathymetry dataset for the entire world in longitude/latitude (at roughly 500m resolution). To use these with GDAL we prepend '/vsicurl/' which nominates the virtual handler to treat a url as a data source. ```R gebco <- "/vsicurl/https://public.services.aad.gov.au/datasets/science/GEBCO_2019_GEOTIFF/GEBCO_2019.tif" srtm <- "/vsicurl/https://opentopography.s3.sdsc.edu/raster/COP30/COP30_hh.vrt" ``` GEBCO 2021 is a global bathymetric product released by the [General Bathymetric Chart of the Oceans (GEBCO)](https://www.gebco.net/data_and_products/gridded_bathymetry_data/gebco_2021/) The data was downloaded in its original NetCDF form and converted to tiled GeoTIFF with overviews (Cloud-optimized COG profile), and is provided by the Australian Antarctic Data Centre in COG form](https://data.aad.gov.au/metadata/GEBCO_2021_GEOTIFF). ```R writeLines(vapour:::gdalinfo_internal(gebco, json = FALSE)) Driver: GTiff/GeoTIFF Files: /vsicurl/https://public.services.aad.gov.au/datasets/science/GEBCO_2019_GEOTIFF/GEBCO_2019.tif Size is 86400, 43200 Coordinate System is: GEOGCRS["WGS 84", DATUM["World Geodetic System 1984", ELLIPSOID["WGS 84",6378137,298.257223563, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], CS[ellipsoidal,2], AXIS["geodetic latitude (Lat)",north, ORDER[1], ANGLEUNIT["degree",0.0174532925199433]], AXIS["geodetic longitude (Lon)",east, ORDER[2], ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4326]] Data axis to CRS axis mapping: 2,1 PROJ.4 string is: '+proj=longlat +datum=WGS84 +no_defs' Origin = (-180.000000000000000,90.000000000000000) Pixel Size = (0.004166666666667,-0.004166666666667) Metadata domains: IMAGE_STRUCTURE (default) DERIVED_SUBDATASETS Metadata: AREA_OR_POINT=Area elevation#long_name=Elevation relative to sea level elevation#sdn_parameter_name=Sea floor height (above mean sea level) {bathymetric height} elevation#sdn_parameter_urn=SDN:P01::ALATZZ01 elevation#sdn_uom_name=Metres elevation#sdn_uom_urn=SDN:P06::ULAA elevation#standard_name=height_above_reference_ellipsoid elevation#units=m lat#axis=Y lat#long_name=latitude lat#sdn_parameter_name=Latitude north lat#sdn_parameter_urn=SDN:P01::ALATZZ01 lat#sdn_uom_name=Degrees north lat#sdn_uom_urn=SDN:P06::DEGN lat#standard_name=latitude lat#units=degrees_north lon#axis=X lon#long_name=longitude lon#sdn_parameter_name=Longitude east lon#sdn_parameter_urn=SDN:P01::ALONZZ01 lon#sdn_uom_name=Degrees east lon#sdn_uom_urn=SDN:P06::DEGE lon#standard_name=longitude lon#units=degrees_east NC_GLOBAL#comment=The data in the GEBCO_2019 Grid should not be used for navigation or any purpose relating to safety at sea. NC_GLOBAL#Conventions=CF-1.6 NC_GLOBAL#history=Information on the development of the data set and the source data sets included in the grid can be found in the data set documentation available from https://www.gebco.net NC_GLOBAL#institution=On behalf of the General Bathymetric Chart of the Oceans (GEBCO), the data are held at the British Oceanographic Data Centre (BODC). NC_GLOBAL#node_offset=1 NC_GLOBAL#references=DOI: 10.5285/836f016a-33be-6ddc-e053-6c86abc0788e NC_GLOBAL#source=The GEBCO_2019 Grid is the latest global bathymetric product released by the General Bathymetric Chart of the Oceans (GEBCO) and has been developed through the Nippon Foundation-GEBCO Seabed 2030 Project. This is a collaborative project between the Nippon Foundation of Japan and GEBCO. The Seabed 2030 Project aims to bring together all available bathymetric data to produce the definitive map of the world ocean floor and make it available to all. NC_GLOBAL#title=The GEBCO_2019 Grid - a continuous terrain model for oceans and land at 15 arc-second intervals Image Structure Metadata: COMPRESSION=DEFLATE INTERLEAVE=BAND LAYOUT=COG Corner Coordinates: Upper Left (-180.0000000, 90.0000000) (180d 0' 0.00"W, 90d 0' 0.00"N) Lower Left (-180.0000000, -90.0000000) (180d 0' 0.00"W, 90d 0' 0.00"S) Upper Right ( 180.0000000, 90.0000000) (180d 0' 0.00"E, 90d 0' 0.00"N) Lower Right ( 180.0000000, -90.0000000) (180d 0' 0.00"E, 90d 0' 0.00"S) Center ( 0.0000000, 0.0000000) ( 0d 0' 0.01"E, 0d 0' 0.01"N) Band 1 Block=512x512 Type=Float32, ColorInterp=Gray NoData Value=9.96920996838686905e+36 Overviews: 43200x21600, 21600x10800, 10800x5400, 5400x2700, 2700x1350, 1350x675, 675x337, 337x168 Unit Type: m Metadata domains: (default) Metadata: long_name=Elevation relative to sea level NETCDF_VARNAME=elevation sdn_parameter_name=Sea floor height (above mean sea level) {bathymetric height} sdn_parameter_urn=SDN:P01::ALATZZ01 sdn_uom_name=Metres sdn_uom_urn=SDN:P06::ULAA standard_name=height_above_reference_ellipsoid units=m ``` The Copernicus DEM is a Digital Surface Model (DSM) which represents the surface of the Earth including buildings, infrastructure and vegetation. This DSM is derived from an edited DSM named WorldDEM, where flattening of water bodies and consistent flow of rivers has been included. In addition, editing of shore- and coastlines, special features such as airports, and implausible terrain structures has also been applied. [OpenTopography data source](https://portal.opentopography.org/raster?opentopoID=OTSDEM.032021.4326.3) URIs of GeoTIFF files that are all included in one VRT (GDAL virtual format) file. ```R writeLines(vapour:::gdalinfo_internal(srtm, json = FALSE)) ... /vsicurl/https://opentopography.s3.sdsc.edu/raster/COP30/COP30_hh/Copernicus_DSM_COG_10_S07_00_E026_00_DEM.tif Size is 1296005, 626400 Coordinate System is: GEOGCRS["WGS 84", DATUM["World Geodetic System 1984", ELLIPSOID["WGS 84",6378137,298.257223563, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], CS[ellipsoidal,2], AXIS["geodetic latitude (Lat)",north, ORDER[1], ANGLEUNIT["degree",0.0174532925199433]], AXIS["geodetic longitude (Lon)",east, ORDER[2], ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4326]] Data axis to CRS axis mapping: 2,1 PROJ.4 string is: '+proj=longlat +datum=WGS84 +no_defs' Origin = (-180.001388888888897,84.000138888888884) Pixel Size = (0.000277777777778,-0.000277777777778) Metadata domains: DERIVED_SUBDATASETS Corner Coordinates: Upper Left (-180.0013889, 84.0001389) (180d 0' 5.00"W, 84d 0' 0.50"N) Lower Left (-180.0013889, -89.9998611) (180d 0' 5.00"W, 89d59'59.50"S) Upper Right ( 180.0000000, 84.0001389) (180d 0' 0.00"E, 84d 0' 0.50"N) Lower Right ( 180.0000000, -89.9998611) (180d 0' 0.00"E, 89d59'59.50"S) Center ( -0.0006944, -2.9998611) ( 0d 0' 2.50"W, 2d59'59.50"S) Band 1 Block=128x128 Type=Float32, ColorInterp=Gray Metadata domains: LocationInfo ``` Show spatial coverage of SRTM tiles ... TBD ## References GEBCO Compilation Group (2021) GEBCO 2021 Grid (doi:10.5285/c6612cbe-50b3-0cff-e053-6c86abc09f8f) European Space Agency, Sinergise (2021). Copernicus Global Digital Elevation Model. Distributed by OpenTopography. https://doi.org/10.5069/G9028PQB. Accessed: 2022-07-19