make_map {webmap}

Create a web map using TNM services

Description

Create a Leaflet map widget that includes base maps offered through The National Map (TNM) cached service endpoints. Information about the content of these base maps can be found within the TNM Base Maps document. TNM content is limited to the United States and territories. The map widget can be rendered on HTML pages generated from R Markdown, Shiny, or other applications.

Usage

make_map(
  maps,
  ...,
  protocol = c("WMTS", "WMS"),
  hydro = FALSE,
  collapse = FALSE
)

Arguments

maps

'character' vector. TNM base maps to include in the web map. Choices include "Topo", "Imagery", "Imagery Topo", "Hydrography", "Shaded Relief", and "Blank". See 'Details' section for a description of each base map. By default, all base maps are included. The one exception is the "Blank" map, which is only accessible using a Web Map Service (WMS), see protocol argument.

...

Arguments to be passed to the leaflet function.

protocol

'character' string. Standard protocol for serving pre-rendered georeferenced TNM map tiles. Select "WMTS" for the Web Map Tile Service (the default) and "WMS" for the Web Map Service.

hydro

'logical' flag. Whether to show or hide (the default) the "Hydrography" overlay base map.

collapse

'logical' flag. Whether the layers control should be rendered as an icon that expands when hovered over. Default is FALSE.

Details

Composite base maps include:

• "Topo" a tile base map that combines the most current TNM data, and other public-domain data, into a multi-scale topographic reference map. Data includes boundaries, geographic names, transportation, contours, hydrography, land cover, shaded relief, and bathymetry.
  

• "Imagery" is a tile base map of orthoimagery in TNM. Orthoimagery data typically are high resolution aerial images that combine the visual attributes of an aerial photograph with the spatial accuracy and reliability of a planimetric map. USGS digital orthoimage resolution may vary from 6 inches to 1 meter.
  

• "Imagery Topo" is a tile base map of orthoimagery in TNM as a backdrop, and a limited selection of topographic data (boundaries, names, transportation, contours, and hydrography).
  

• "Hydrography" is a overlay of cartographic representation of the National Hydrography Dataset (NHD). The NHD is a comprehensive set of digital geospatial data that encodes information about naturally occurring and constructed bodies of surface water, paths through which water flows, related features such as stream gages and dams, and additional hydrologic information.
  

• "Shaded Relief" is a tile base map of terrain representation in the form of hillshades created from the 3D Elevation Program (3DEP). 3DEP maintains a seamless dataset of best available raster elevation data, in the form of digital elevation models (DEMs) for the conterminous United States, Alaska, Hawaii, and Territorial Islands of the United States.
  

• "OSM" is the OpenStreetMap tile base map.
  

• "Blank" consists of ocean tints to give the outline of land cover as an empty base map.
  

Value

An object of class 'leaflet', a hypertext markup language (HTML) map widget. See example for instructions on how to add additional graphic layers (such as points, lines, and polygons) to the map widget. Graphic layers added to the web map must be in latitude and longitude using WGS 84 (also known as EPSG:4326).

Author(s)

J.C. Fisher, U.S. Geological Survey, Idaho Water Science Center

Examples

# Create map widget
map <- make_map()

# Print map widget
map

# Print map with markers
pts <- rbind(
  c(-112.049, 43.517),
  c(-122.171, 37.456),
  c( -77.367, 38.947),
  c(-149.803, 61.187),
  c( -80.248, 26.080)
)
leaflet::addMarkers(map,
  lng = pts[, 1],
  lat = pts[, 2]
)

# Print map of satellite imagery with a rectangle in the vicinity of UCLA
make_map(
  maps = "Imagery",
  collapse = TRUE
) |>
  leaflet::addRectangles(
    lng1 = -118.456,
    lat1 =   34.078,
    lng2 = -118.436,
    lat2 =   34.062,
    fillColor = "transparent"
  )