Creates a tmap-element
that draws a tile layer. This feature is only available in view mode. For plot mode, a tile image can be retrieved by read_osm
. The function tm_basemap
draws the tile layer as basemap (i.e. as bottom layer), whereas tm_tiles
draws the tile layer as overlay layer (where the stacking order corresponds to the order in which this layer is called). Note that basemaps are shown by default (see details).
Usage
tm_basemap(server = NA, group = NA, alpha = NA, tms = FALSE)
tm_tiles(server, group = NA, alpha = 1, zindex = NA, tms = FALSE)
Arguments
- server
name of the provider or an URL. The list of available providers can be obtained with
providers
(tip: in RStudio, typeproviders$
to see the options). See https://leaflet-extras.github.io/leaflet-providers/preview/ for a preview of those. When a URL is provided, it should be in template format, e.g."https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
. UseNULL
intm_basemap
to disable the basemaps.- group
name of the group to which this layer belongs in view mode. Each group can be selected or deselected in the layer control item. Set
group = NULL
to hide the layer in the layer control item. By default, it will be set to the name of the shape (specified intm_shape
). Tile layers generated withtm_basemap
will be base groups whereas tile layers generated withtm_tiles
will be overlay groups.- alpha
alpha
- tms
is the provided tile server defined according to the TMS protocol? By default
FALSE
.- zindex
zindex of the pane in view mode. By default, it is set to the layer number plus 400. By default, the tmap layers will therefore be placed in the custom panes
"tmap401"
,"tmap402"
, etc., except for the base tile layers, which are placed in the standard"tile"
. This parameter determines both the name of the pane and the z-index, which determines the pane order from bottom to top. For instance, ifzindex
is set to 500, the pane will be named"tmap500"
.
Details
When tm_basemap
is not specified, the default basemaps are shown, which can be configured by the basemaps
arugument in tmap_options
. By default (for style "white"
) three basemaps are drawn: c("Esri.WorldGrayCanvas", "OpenStreetMap", "Esri.WorldTopoMap")
. To disable basemaps, add tm_basemap(NULL)
to the plot, or set tmap_options(basemaps = NULL)
. Similarly, when tm_tiles
is not specified, the overlay maps specified by the overlays
argument in in tmap_options
are shown as front layer. By default, this argument is set to NULL
, so no overlay maps are shown by default. See examples.
Examples
if (FALSE) {
current.mode <- tmap_mode("view")
data(World, metro)
tm_basemap(leaflet::providers$Stamen.Watercolor) +
tm_shape(metro, bbox = "India") + tm_dots(col = "red", group = "Metropolitan areas") +
tm_tiles(paste0("http://services.arcgisonline.com/arcgis/rest/services/Canvas/",
"World_Light_Gray_Reference/MapServer/tile/{z}/{y}/{x}"), group = "Labels")
# Use tmap options to set the basemap and overlay map permanently during the R session:
opts <- tmap_options(basemaps = c(Canvas = "Esri.WorldGrayCanvas", Imagery = "Esri.WorldImagery"),
overlays = c(Labels = paste0("http://services.arcgisonline.com/arcgis/rest/services/Canvas/",
"World_Light_Gray_Reference/MapServer/tile/{z}/{y}/{x}")))
qtm(World, fill = "HPI", fill.palette = "RdYlGn")
# restore options
tmap_options(opts)
# restore current mode
tmap_mode(current.mode)
}