Start and/or stop automagic mapviewing of spatial objects in your workspace.

Source: R/watch.R

Use these functions to enable automatic vieweing of all spatial objects currently available in env. mapviewWatcher uses later to set up a watcher function that continuously monitors env for spatial objects and refreshes the viewer/browser in case the list of spatial objects changes.

startWatching and stopWatching are convenience functions to start and stop watching, respectively.

mapviewWatcher(env = .GlobalEnv, ...)

startWatching(env = .GlobalEnv, ...)

stopWatching(env = .GlobalEnv, ...)

Arguments

env

the environemnt that is being watched (default is .GlobalEnv).

...

currently not used.

Details

mapviewWatcher uses identical and hence will redraw even if e.g. the attributes of a spatial object are changed only slightly. By default mapviewWatcher watches the .GlobalEnv but this can be changed to another environment. Whether watching is turned on is controlled by mapviewGetOption("watch"). In order to enable watching it needs to be set to mapviewOptions(watch = TRUE) (default is FALSE) and the watcher needs to be initiated by calling mapviewWatcher() once. To switch watching off it is sufficient to set mapviewOptions(watch = FALSE).

Functions

  • startWatching(): start watching

  • stopWatching(): stop watching

Examples

  if (interactive()) {
    library(mapview)

    ## start the watcher
    mapview::startWatching()

    ## load some data and watch the automatic visualisation
    fran = mapview::franconia
    brew = mapview::breweries

    ## stop the watcher
    mapview::stopWatching()

    ## loading or removing things now will not trigger a view update
    rm(brew)
    trls = mapview::trails

    ## re-starting the viewer will re-draw whatever is currently available
    mapview::startWatching()

    ## watcher can also be stopped via mapviewOptions
    mapviewOptions(watch = FALSE)

    rm(trls)

  }