In martinjhnhadley/oidnChaRts: Utility Functions For htmlwidget Visualisations

Overview of function

geo_marker_plot can be used to create the following kinds of charts:

Geo marker plot

Geo marker plots contain markers that highlight important geographic positions, the markers may differ in colour but do not use size as a channel for communicating data. For charts where geographic positions should be represented as circles of differing sizes, refer to geo_bubble_chart instead.

data_geo_marker_plot %>%
  geo_marker_plot(library = "leaflet",
                  mouseover.text = ~city,
                  popup.text = ~paste("Country:",country, "<br>", "City:", city))

As with all oidnChaRts libraries, you are advised to load the htmlwidget library you're using directly.

data_stacked_bar_chart

library(oidnChaRts)

This vignette covers the use of geo marker plots for visualising data with a variety of htmlwidget libraries, for demonstration purposes we use the following dataset generated from https://doi.org/10.6084/m9.figshare.4516772.

head(data_geo_marker_plot)

The data is generated from a historical analysis of the letters sent between German migrants and their families between the 18th and 19th Centuries, the columns may be summarised as follows:

location.name: Country, City (state, if relevant)
latitude: Latitude of location
longitude: Longitude of location
count: number of times location

Geo marker plot specifications

In Geo marker plots the only channels of information (i.e. what can vary between data points) are as follows:

position: the longitude, latitude of the data point
colour: colour of the markers

However, it must be noted that geo marker icons are typcially implemented as .png images and therefore it is not generally possible to have n different colours of markers. For this reason, the geo_marker_plot function provides absolutely minimal flexibility in the appearance of your output.

At the time of writing (r Sys.Date()) the only library with good support for geo markers is leaflet. You're strongly recommended to build these charts from scratch, following the documentation here: http://rstudio.github.io/leaflet/markers.html.

Geo marker plot

The following will create a generic geo marker plot with leaflet:

data_geo_marker_plot %>%
  geo_marker_plot(library = "leaflet")

Mouseover text

Mouseover text is supported in the leaflet library as follows:

data_geo_marker_plot %>%
  geo_marker_plot(library = "leaflet",
                  mouseover.text = ~country)

Popup text

Popup text (which is shown when a marker is clicked) is supported for leaflet as follows:

data_geo_marker_plot %>%
  geo_marker_plot(library = "leaflet",
                  mouseover.text = ~city,
                  popup.text = ~paste("Country:",country, "<br>", "City:", city))