mapview options

(CC-BY-NC-SA)

This document was produced on So Jun 12 2016 using mapview version 1.1.0

mapviewOptions() can be used to set several plotting parameters (arguments) globally, meaning that they will be valid for as long as the session is active.

A call to mapviewOptions() will show all options and their default values in the console

library(mapview)

mapviewOptions()

## platform            : leaflet 
## basemaps            : CartoDB.Positron OpenStreetMap Esri.WorldImagery Thunderforest.Landscape OpenTopoMap 
## raster.size         : 8388608 
## mapview.maxpixels   : 5e+05 
## plainview.maxpixels : 1e+07 
## maxpolygons         : 30000 
## maxpoints           : 20000 
## maxlines            : 30000 
## raster.palette      : 
## function (n, alpha = 1, begin = 0, end = 1) 
## {
##     viridis(n, alpha, begin, end, option = "inferno")
## }
## <environment: namespace:viridisLite>
## 
## vector.palette      : 
## function (n, alpha = 1, begin = 0, end = 1, option = "D") 
## {
##     if (begin < 0 | begin > 1 | end < 0 | end > 1) {
##         stop("begin and end must be in [0,1]")
##     }
##     option <- switch(option, A = "A", magma = "A", B = "B", inferno = "B", 
##         C = "C", plasma = "C", D = "D", viridis = "D", {
##             warning(paste0("Option '", option, "' does not exist. Defaulting to 'viridis'."))
##             "D"
##         })
##     map <- viridisLite::viridis.map[viridisLite::viridis.map$opt == 
##         option, ]
##     map_cols <- grDevices::rgb(map$R, map$G, map$B)
##     fn_cols <- grDevices::colorRamp(map_cols, space = "Lab", 
##         interpolate = "spline")
##     cols <- fn_cols(seq(begin, end, length.out = n))/255
##     grDevices::rgb(cols[, 1], cols[, 2], cols[, 3], alpha = alpha)
## }
## <environment: namespace:viridisLite>
## 
## verbose             : FALSE 
## na.color            : #BEBEBE80 
## legend              : FALSE 
## legend.pos          : topright 
## layers.control.pos  : topleft 
## leafletWidth  : 
## leafletHeight  :

In detail, these are:

platform - the rendeing platform. At the moment, only leaflet is accepted but we are planning to implement more in the future
basemaps - the default map.types used by mapview
raster.size - the maximum number of bytes to allow for the projected raster image rendering (before base64 encoding) -> default 8MB
mapview.maxpixels - the maximum number of pixels to allow for raster image rendering on the map background -> default 500k
plainview.maxpixels - the maximum number of pixels to allow for plain raster image rendering without the map background -> default 1 Million
maxpolygons - the maximum number of polygons to allow for polygon rendering using standard leaflet (package) implementation. If an object has more features than this threshold, special canvas shader rendering is used. Note that this will result in less flexible rendering as many of the standard arguments will not be available (e.g. color mapping). -> default 30k
maxpoints - as for maxpolygons but for point features -> default 20k
maxlines - as for maxpolygons but for line features -> default 30k
raster.palette - the default palette used for rendering raster images -> default viridisLite::inferno
vector.palette - the default palette used for rendering vector features -> default viridisLite::viridis
verbose - whether to print more verbose information to the console during the rendering -> default FALSE
na.color - the color to be used for rendering NA values -> default #BEBEBE80
legend - whether to plot a legend -> default FALSE
legend.pos - where to position the legend if shown -> default topright
layers.control.pos - where to position the layers control on the map -> default topleft
leafletWidth, leafletHeight - the width and height of the map widget -> defaul NULL which means that the browser will be filled if possible

To get the current value of a certain option use mapviewGetOption()

mapviewGetOption("basemaps")

## [1] "CartoDB.Positron"        "OpenStreetMap"          
## [3] "Esri.WorldImagery"       "Thunderforest.Landscape"
## [5] "OpenTopoMap"

To set certain options use mapviewOptions()

library(RColorBrewer)

mapviewOptions(basemaps = c("CartoDB.DarkMatter", "OpenStreetMap.DE"),
               raster.palette = colorRampPalette(brewer.pal(9, "Greys")),
               vector.palette = colorRampPalette(brewer.pal(9, "YlGnBu")),
               na.color = "magenta",
               layers.control.pos = "topright")

mapview(breweries91, zcol = "founded", legend = TRUE)

These options will now be available until the current session is closed. i.e. you quit R

mapview(poppendorf[[5]])

viewRGB(poppendorf, 5, 4, 3)

To change these options permanently, i.e. across sessions, you could place a call to mapviewOptions() in your .Rprofile so that they will be set everytime you start R