leaflet: Create a Leaflet web-map

Description

Creates a web-map of users' spatial data over open base maps. Output consists of a ready to use HTML file (and a GeoJSON/TopoJSON data file).

Usage

leaflet(data, dest, title, size, base.map="osm", center, zoom,  style, popup, label, controls="all", incl.data=FALSE, overwrite=TRUE)
leaf(data, dest, title, size, base.map="osm", center, zoom,  style, popup, label, controls="all", incl.data=FALSE, overwrite=TRUE)

Arguments

data

Name(s) of data file(s) (GeoJSON/TopoJSON format), as string or a list of strings. Plotting order follows the file sequence.

dest

Path to the data file, as string. Optional -- if missing, the current working directory is used.

title

Map title, as string. Default is "map".

size

Size of the map on the website in pixels, as numeric vector -- c(width, height). Optional -- if missing, a fullscreen (browser window) map is generated.

base.map

Base map(s) in the background of the data, as string. One or a list of "osm" (OpenStreetMap standard map), "tls" (Thunderforest Landscape), "mqosm" (MapQuest OSM), "mqsat" (MapQuest Open Aerial), "water" (Stamen Watercolor), "toner" (Stamen Toner), "tonerbg" (Stamen Toner background), "tonerlite" (Stamen Toner lite), "positron" (CartoDB Positron) or "darkmatter" (CartoDB Dark matter). Default is "osm". If base.map is a list, the last item is used as default base map and a layer control button is added to the map.

center

Map center coordinates in decimal degrees, as vector of two numeric values: c(latitude, longitude). Optional -- if missing, the data layer is centered automatically. code has to be specified to use center.

zoom

Map zoom level, as integer value. Usually a value between 0 (global small scale) and 18 (detailed large scale). The MapQuest Open Aerial map (base.map="mqsat") provides only 12 zoom levels [0-11]. Optional -- if missing, the zoom level is calculated for the bounding box of the data layer. center has to be specified to use zoom.

style

Style(s) of the data layer(s). One or a list of style object(s), created by styleSingle, styleGrad or styleCat. Optional -- if missing, a default style is applied.

popup

Properties (attributes) of the data to be shown in a popup when a map object is clicked. String or a vector of strings. "*" adds all available properties to the popup. A list of (vectors of) strings specifies properties for multiple data layers. Per default no popups are shown.

label

Property (attribute) of the data to be shown in a dynamic label, as string. A list of strings specifies properties for multiple data layers. Per default no labels are shown. Only point data is supported and markers do not work very well.

controls

List of controls to be added to the map. Available controls are "zoom", "scale", "layer" and "legend". "all" (the default) adds all controls. Controls are only added if necessary, e.g. in case of one data layer there is no legend. NA omits all controls. Note: data layer controls only appear if incl.data is set to TRUE.

incl.data

If TRUE, data is included in the HTML file itself. Per default (incl.data=FALSE) the data is saved in a separate file. Including data in the HTML file allows for viewing the map locally on some browsers (e.g. Chrome and Opera).

overwrite

TRUE (which is the default) overwrites existing files with the same name.

Value

References

Base map tiles are provided by

	OpenStreetMap standard map
http://www.openstreetmap.org
Thunderforest Landscape	http://www.thunderforest.com
	MapQuest OSM
http://www.mapquest.com
MapQuest Open Aerial	http://www.mapquest.com
	Stamen Watercolor
http://stamen.com
Stamen Toner	http://stamen.com
	Stamen Toner background
http://stamen.com
Stamen Toner lite	http://stamen.com
	CartoDB Positron
http://cartodb.com

Examples

Run this code

## Not run: 
# # prepare data
# data(quakes)
# dat <- toGeoJSON(data=quakes, dest=tempdir())
# 
# # create and view simple map
# map <- leaflet(dat, dest=tempdir())
# map  # redirects to browseURL(map)
# 
# # set output directory and map title
# map <- leaflet(data=dat, dest=tempdir(), title="Fiji Earthquakes")
# 
# # set map size, center and zoom level
# map <- leaflet(data=dat, dest=tempdir(), 
#   size=c(800,600), center=c(-18.35, 179.75), zoom=6)
# 
# # set base map and popup/label
# # magnitude is used as popup (type names(quakes) for available properties)
# map <- leaflet(data=dat, dest=tempdir(), 
#   base.map="mqsat", popup="stations", label="mag")
#   
# # minimalist? - no base map
# map <- leaflet(data=dat, dest=tempdir(), 
#   base.map=NA, popup="mag")
# 
# # include data in HTML file
# map <- leaflet(dat, dest=tempdir(), incl.data=TRUE)
# 
# # preserve existing files from overwriting
# map <- leaflet(dat, dest=tempdir(), overwrite=FALSE)
# 
# # more than one base map
# map <- leaflet(data=dat, dest=tempdir(), 
#   base.map=list("osm", "mqsat", "tls"))
# 
# # multiple properties in the popup
# map <- leaflet(data=dat, dest=tempdir(), 
#   popup=c("mag", "depth"))
# 
# # all available properties in the popup
# map <- leaflet(data=dat, dest=tempdir(), 
#   popup="*")
# 
# # change style
# sty <- styleSingle(col="red", fill=NA)
# map <- leaflet(data=dat, dest=tempdir(), base.map="mqsat", style=sty)
# 
# # controls
# map <- leaflet(data=dat, dest=tempdir(), controls=NA)  # no controls
# map <- leaflet(data=dat, dest=tempdir(), controls="scale")  # scale only
# map <- leaflet(data=dat, dest=tempdir(), controls=c("zoom", "scale"))
# 
# # more than one data set
# park <- system.file(package="leafletR", "files", "park_sk.geojson")
# peak <- toGeoJSON(system.file(package="leafletR", "files", "peak_sk.kmz"), 
#   dest=tempdir())  # httr package required
# sty.1 <- styleSingle(col="green", fill="green")
# sty.2 <- styleSingle(col="brown", fill="brown", rad=3)
# map <- leaflet(data=list(park, peak), dest=tempdir(), 
#   style=list(sty.1, sty.2), popup=list("*", "Name"))
# 
# # names in legend
# # note: "_" and "." are replaced with blanks in the legend 
# map <- leaflet(data=list(National_Parks=park, Peaks.above.600.m)=peak), 
#   dest=tempdir(), style=list(sty.1, sty.2), popup=list("*", "Name"))
# ## End(Not run)

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