add_terrain: Add terrain

In mapdeck: Interactive Maps Using 'Mapbox GL JS' and 'Deck.gl'

Description

Adds mesh surfaces from height map images

Usage

add_terrain(
  map,
  layer_id = NULL,
  elevation_data,
  texture = NULL,
  elevation_decoder = c(1, 0, 0, 0),
  bounds = NULL,
  max_error = 4,
  update_view = TRUE,
  focus_layer = FALSE
)

Arguments

map	a mapdeck map object
layer_id	single value specifying an id for the layer. Use this value to distinguish between shape layers of the same type. Layers with the same id are likely to conflict and not plot correctly
elevation_data	Image URL that encodes height data. When elevation_data is a URL template, i.e. a string containing 'x' and 'y', it loads terrain tiles on demand and renders a mesh for each tile. If elevation_data is an absolute URL, as ingle mesh is used, and the bounds argument is required to position it into the world space.
texture	Image URL to use as the texture
elevation_decoder	Four value used to convert a pixel to elevation in metres. The values correspond to rScale, gScale, bScale, offset. See details
bounds	Four values ( c(left, bottom, right, top) . bounds of the image to fit in x,y coordinates into. left and right referes to the world longitude/x at the corresponding side of the image. top and bottom refers to the world latitude/y at the corresponding side of the image. Must be supplied when using non-tiled elevation_data
max_error	Martini error tolerance in metres, smaller number results in more detailed mesh.
update_view	logical indicating if the map should update the bounds to include this layer
focus_layer	logical indicating if the map should update the bounds to only include this layer

Details

The elevation_decoder contains four values representing

• rScale - Multiplier of the red channel

• gScale - Multiplier of the green channel

• bScale - Multiplier of the blue channel

• offset - translation of the sum

Each colour channel is a number between [0, 255].

Examples

set_token( "MAPBOX_TOKEN" )
## Digital elevation model from https://www.usgs.gov/
elevation <- 'https://raw.githubusercontent.com/visgl/deck.gl-data/master/website/terrain.png'
texture <- 'https://raw.githubusercontent.com/visgl/deck.gl-data/master/website/terrain-mask.png'
bounds <- c(-122.5233, 37.6493, -122.3566, 37.8159)

mapdeck() %>%
  add_terrain(
    , elevation_data = elevation
    , elevation_decoder = c(1,0,0,0)
    , texture = texture
    , bounds = bounds
    , max_error = 1
  )

mapdeck documentation built on Sept. 4, 2020, 9:07 a.m.