3. mapview options

Source: vignettes/articles/mapview_03-options.Rmd

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

## 
##  global options: 
## 
## platform            : leaflet 
## basemaps            : CartoDB.Positron CartoDB.DarkMatter OpenStreetMap Esri.WorldImagery OpenTopoMap 
## raster.palette      : function (n)  
## vector.palette      : function (n)  
## verbose             : FALSE 
## na.color            : #BEBEBE80 
## legend              : TRUE 
## legend.opacity      : 1 
## legend.pos          : topright 
## layers.control.pos  : topleft 
## leafletWidth        : 
## leafletHeight       : 
## viewer.suppress     : FALSE 
## homebutton          : TRUE 
## homebutton.pos      : bottomright 
## native.crs          : FALSE 
## watch               : FALSE 
## 
##  raster data related options: 
## 
## raster.size         : 8388608 
## mapview.maxpixels   : 5e+05 
## plainview.maxpixels : 1e+07 
## use.layer.names     : FALSE 
## trim                : TRUE 
## method              : bilinear 
## query.type          : mousemove 
## query.digits        : 7 
## query.position      : topright 
## query.prefix        : Layer 
## georaster           : FALSE 
## 
##  vector data related options: 
## 
## maxpolygons         : 30000 
## maxpoints           : 20000 
## maxlines            : 30000 
## pane                : auto 
## cex                 : 6 
## alpha               : 0.9 
## fgb                 : FALSE

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 hcl.colors(n, palette = "Inferno")
  • vector.palette - the default palette used for rendering vector features -> default hcl.colors(n, palette = "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"   "CartoDB.DarkMatter" "OpenStreetMap"     
## [4] "Esri.WorldImagery"  "OpenTopoMap"

To set certain options use mapviewOptions()

mapviewOptions(basemaps = c("Esri.WorldShadedRelief", "OpenStreetMap.DE"),
               raster.palette = grey.colors,
               vector.palette = colorRampPalette(c("snow", "cornflowerblue", "grey10")),
               na.color = "magenta",
               layers.control.pos = "topright")
## 
##  global options: 
## 
## platform            : leaflet 
## basemaps            : Esri.WorldShadedRelief OpenStreetMap.DE 
## raster.palette      : function (n, start = 0.3, end = 0.9, gamma = 2.2, alpha, rev = FALSE)  
## vector.palette      : function (n)  
## verbose             : FALSE 
## na.color            : magenta 
## legend              : TRUE 
## legend.opacity      : 1 
## legend.pos          : topright 
## layers.control.pos  : topright 
## leafletWidth        : 
## leafletHeight       : 
## viewer.suppress     : FALSE 
## homebutton          : TRUE 
## homebutton.pos      : bottomright 
## native.crs          : FALSE 
## watch               : FALSE 
## 
##  raster data related options: 
## 
## raster.size         : 8388608 
## mapview.maxpixels   : 5e+05 
## plainview.maxpixels : 1e+07 
## use.layer.names     : FALSE 
## trim                : TRUE 
## method              : bilinear 
## query.type          : mousemove 
## query.digits        : 7 
## query.position      : topright 
## query.prefix        : Layer 
## georaster           : FALSE 
## 
##  vector data related options: 
## 
## maxpolygons         : 30000 
## maxpoints           : 20000 
## maxlines            : 30000 
## pane                : auto 
## cex                 : 6 
## alpha               : 0.9 
## fgb                 : FALSE
mapview(breweries, zcol = "founded", legend = TRUE)

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

library(plainview)

mapview(poppendorf[[5]])
## Warning in wkt(projfrom): CRS object has no comment
## Warning in showSRID(uprojargs, format = "PROJ", multiline = "NO", prefer_proj =
## prefer_proj): Discarded ellps WGS 84 in Proj4 definition: +proj=merc +a=6378137
## +b=6378137 +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null
## +wktext +no_defs +type=crs
## Warning in showSRID(uprojargs, format = "PROJ", multiline = "NO", prefer_proj =
## prefer_proj): Discarded datum World Geodetic System 1984 in Proj4 definition
## Warning in wkt(pfrom): CRS object has no comment
## Warning in rgdal::rawTransform(projfrom, projto, nrow(xy), xy[, 1], xy[, : Using
## PROJ not WKT2 strings
## Warning in wkt(pfrom): CRS object has no comment
## Warning in rgdal::rawTransform(projfrom, projto, nrow(xy), xy[, 1], xy[, : Using
## PROJ not WKT2 strings
## Warning in rgdal::rawTransform(projto_int, projfrom, nrow(xy), xy[, 1], : Using
## PROJ not WKT2 strings
## Warning in showSRID(uprojargs, format = "PROJ", multiline = "NO", prefer_proj =
## prefer_proj): Discarded ellps WGS 84 in Proj4 definition: +proj=merc +a=6378137
## +b=6378137 +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null
## +wktext +no_defs +type=crs
## Warning in showSRID(uprojargs, format = "PROJ", multiline = "NO", prefer_proj =
## prefer_proj): Discarded datum World Geodetic System 1984 in Proj4 definition

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

To revert to factory settings use default = TRUE

mapviewOptions(default = TRUE)
mapview(franconia)