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elevatr (version 0.99.0)

get_aws_terrain: Get a digital elevation model from the AWS Terrain Tiles

Description

This function uses the AWS Terrain Tile service to retrieve an elevation raster from the geotiff service. It accepts a sf::st_bbox object as input and returns a single raster object covering that extent.

Usage

get_aws_terrain(
  locations,
  z,
  prj,
  expand = NULL,
  ncpu = future::availableCores() - 1,
  serial = NULL,
  ...
)

Arguments

locations

Either a data.frame of x (long) and y (lat), an sp, sf, or raster object as input.

z

The zoom level to return. The zoom ranges from 1 to 14. Resolution of the resultant raster is determined by the zoom and latitude. For details on zoom and resolution see the documentation from Mapzen at https://github.com/tilezen/joerd/blob/master/docs/data-sources.md#what-is-the-ground-resolution

prj

A valid input to st_crs If a sf object or a terra object is provided as the locations, the prj is optional and will be taken from locations. This argument is required for a data.frame of locations.

expand

A numeric value of a distance, in map units, used to expand the bounding box that is used to fetch the terrain tiles. This can be used for features that fall close to the edge of a tile and additional area around the feature is desired. Default is NULL.

ncpu

Number of CPU's to use when downloading aws tiles.

serial

Logical to determine if API should be hit in serial or in parallel. TRUE will use purrr, FALSE will use furrr.

...

Extra configuration parameters to be passed to httr::GET. Common usage is to adjust timeout. This is done as config=timeout(x) where x is a numeric value in seconds. Multiple configuration functions may be passed as a vector.