tmap (version 3.3)

tm_view: Options for the interactive tmap viewer

Description

Set the options for the interactive tmap viewer. Some of these options can also be set with tm_layout, since they are style dependent (e.g., the choice of basemaps). The function tm_view overrides these options when specified.

Usage

tm_view(
  alpha,
  colorNA,
  projection,
  symbol.size.fixed,
  dot.size.fixed,
  text.size.variable,
  bbox,
  set.bounds,
  set.view,
  set.zoom.limits,
  view.legend.position,
  control.position,
  legend.position,
  leaflet.options
)

Arguments

alpha

transparency (opacity) parameter applied to whole map. By default, it is set to 0.7 if basemaps are used, and 1 otherwise.

colorNA

default color for missing values in interactive mode. If the color of missing values is not defined in the layer functions (e.g. tm_fill), then the default color is taken from the na value of the aes.color argument in tm_layout. This colorNA argument (if not NA itself) overrides that default value. For interactive maps, it can be useful to set colorNA to NULL, which means transparent.

projection

projection. Either a EPSG number, or a leaflet_crs object created with leafletCRS. By default, the Web Mercator (3857) is used, since the vast majority of basemaps are rendered accordingly. Other standards are EPSG numbers 4326 (WGS84) and 3395 (Mercator). If set to 0, the projection of the master shape is used (see tm_shape) provided that a EPSG number can be extracted.

symbol.size.fixed

should symbol sizes be fixed while zooming?

dot.size.fixed

should dot sizes be fixed while zooming?

text.size.variable

should text size variables be allowed in view mode? By default FALSE, since in many applications, the main reason to vary text size is to prevent occlusion in plot mode, which is often not a problem in view mode due to the ability to zoom in.

bbox

bounding box. One of the following:

• A bounding box (an sf bbox object, see st_bbox, or object that can be read by bb.

• Open Street Map search query. The bounding is automatically generated by querying q from Open Street Map Nominatim. See https://wiki.openstreetmap.org/wiki/Nominatim.

If set, it overrides set.view and all bbox arguments of tm_shape.

set.bounds

logical that determines whether maximum bounds are set, or a numeric vector of four values that specify the lng1, lat1, lng2, and lat2 coordinates (see setMaxBounds).

set.view

numeric vector that determines the view. Either a vector of three: lng, lat, and zoom, or a single value: zoom. See setView. Only applicable if bbox is not specified

set.zoom.limits

numeric vector of two that set the minimum and maximum zoom levels (see tileOptions).

view.legend.position

Character vector of two values, specifying the position of the legend. Use "left" or "right" for the first value and "top" or "bottom" for the second value. It overrides the value of legend.position of tm_layout, unless set to NA.

control.position

Character vector of two values, specifying the position of the layer control UI. Use "left" or "right" for the first value and "top" or "bottom" for the second value.

legend.position

not used anymore, renamed to view.legend.position

leaflet.options

other options passed on via leafletOptions to leaflet.js map creation (see leaflet, follow Docs, Map, Creation). Named list, where the names correspond to the variable names. Tip: use zoomSnap and zoomDelta for fractional zooming.

References

Tennekes, M., 2018, tmap: Thematic Maps in R, Journal of Statistical Software, 84(6), 1-39, 10.18637/jss.v084.i06

See Also

vignette("tmap-getstarted")

Examples

# NOT RUN {
# world choropleth/bubble map of the world
data(World, metro)
metro$growth <- (metro$pop2020 - metro$pop2010) / (metro$pop2010 * 10) * 100

map1 <- tm_shape(metro) +
	tm_bubbles("pop2010", col = "growth", 
		border.col = "black", border.alpha = .5, 
		style="fixed", breaks=c(-Inf, seq(0, 6, by=2), Inf),
		palette="-RdYlBu", contrast=1, 
		title.size="Metro population", 
		title.col="Growth rate (%)", id="name", 
		    popup.vars=c("pop2010", "pop2020", "growth")) + 
	tm_legend(outside=TRUE)

current.mode <- tmap_mode("plot")

# plot map
map1

# view map with default view options
tmap_mode("view")
map1

# view map with changed view options
map1 + tm_view(set.view = c(7, 51, 4)) # longitude 7, latitude 51, zoom 4

# interactive world map in original CRS
tm_shape(World) +tm_polygons("HPI") + tm_view(projection = 0) + tm_basemap(NULL)

# restore current mode
tmap_mode(current.mode)
# }