gvisGeoMap {googleVis}

Google Geo Map with R

Package:

googleVis

Version:

0.4.2

Description

The gvisGeoMap function reads a data.frame and creates text output referring to the Google Visualisation API, which can be included into a web page, or as a stand-alone page. A geo map is a map of a country, continent, or region map, with colours and values assigned to specific regions. Values are displayed as a colour scale, and you can specify optional hover-text for regions. The map is rendered in the browser. Note that the map is not scroll-able or drag-gable, but can be configured to allow zooming.

Usage

gvisGeoMap(data, locationvar=”, numvar=”, hovervar=”,
           options = list(), chartid)

Arguments

data

a data.frame. The data has to have at least two columns with location name (locationvar), value to be mapped to location (numvar) and an optional variable to display any text while the mouse hovers over the location (hovervar).

locationvar

column name of data with the geo locations to be analysed. The locations can be provide in two formats:

Format 1: 'latitude:longitude'. See the example below.
Format 2: Address, country name, region name locations, or US metropolitan area codes, see http://code.google.com/apis/adwords/docs/developer/adwords_api_us_metros.html. This format works with the dataMode option set to either 'markers' or 'regions'. The following formats are accepted: A specific address (for example, "1600 Pennsylvania Ave"). A country name as a string (for example, "England"), or an uppercase ISO-3166 code or its English text equivalent (for example, "GB" or "United Kingdom"). An uppercase ISO-3166-2 region code name or its English text equivalent (for example, "US-NJ" or "New Jersey").

numvar

column name of data with the numeric value displayed when the user hovers over this region.

hovervar

column name of data with the additional string text displayed when the user hovers over this region.

options

list of configuration options for Google Geo Map.

gvis.editor: a character label for an on-page button which opens an in-page dialog box that enables users to edit, change and customise the chart. By default no value is given and therefore no button is displayed.

Further possible components are, taken from https://google-developers.appspot.com/chart/interactive/docs/gallery/geomap.html#Configuration_Options:

region

string, default 'world'. The area to display on the map. (Surrounding areas will be displayed as well.) Can be either a country code (in uppercase ISO-3166 format), or a one of the following strings

world	(Whole world)
us_metro	(United States, metro areas)
005	(South America)
013	(Central America)
021	(North America)
002	(All of Africa)
017	(Central Africa)
015	(Northern Africa)
018	(Southern Africa)
030	(Eastern Asia)
034	(Southern Asia)
035	(Asia/Pacific region)
143	(Central Asia)
145	(Middle East)
151	(Northern Asia)
154	(Northern Europe)
155	(Western Europe)
039	(Southern Europe)

Geomap does not enable scrolling or dragging behavior, and only limited zooming behavior. A basic zoom out can be enabled by setting the showZoomOut property.

dataMode

string, default 'regions'. How to display values on the map. Two values are supported:

regions - Colors a whole region with the appropriate color. This option cannot be used with latitude/longitude addresses. See Regions Example. markers - Displays a dot over a region, with the color and size indicating the value. See Markers Example.

width

string, default '556px'. Width of the visualization. If no units are given, the default unit is pixels.

height

default, string '347px'. Height of the visualization. If no units are given, the default unit is pixels.

colors

a JSON array of RGB numbers in the format 0xRRGGBB [0xE0FFD4, 0xA5EF63, 0x50AA00, 0x267114]. Color gradient to assign to values in the visualization. You must have at least two values; the gradient will include all your values, plus calculated intermediary values, with the lightest color as the smallest value, and the darkest color as the highest.

showLegend

boolean, default TRUE. If true, display a legend for the map.

showZoomOut

boolean, default FALSE. If true, display a button with the label specified by the zoomOutLabel property. Note that this button does nothing when clicked, except throw the zoomOut event. To handle zooming, catch this event and change the region option. You can only specify showZoomOut if the region option is smaller than the world view. One way of enabling zoom in behavior would be to listen for the regionClick event, change the region property to the appropriate region, and reload the map.

zoomOutLabel

string, default 'Zoom Out'. Label for the zoom button.

gvis.listener.jscode

character string which will be placed inside select event. A valid value is alert('a region was selected');. You may also use the method getSelection.

chartid

character. If missing (default) a random chart id will be generated based on chart type and tempfile

Values

gvisGeoMap returns list of class "gvis" and "list". An object of class "gvis" is a list containing at least the following components:

type

Google visualisation type, here 'GeoMap'

chartid

character id of the chart object. Unique chart ids are required to place several charts on the same page.

html

a list with the building blocks for a page

header

a character string of a html page header: <html>...<body>,

chart

a named character vector of the chart's building blocks:

jsHeader: Opening <script> tag and reference to Google's JavaScript library.
jsData: JavaScript function defining the input data as a JSON object.
jsDrawChart: JavaScript function combing the data with the visualisation API and user options.
jsDisplayChart: JavaScript function calling the handler to display the chart.
jsFooter: End tag </script>.
jsChart: Call of the jsDisplayChart function.
divChart: <div> container to embed the chart into the page.

caption

character string of a standard caption, including data name and chart id.

footer

character string of a html page footer: </body>...</html>, including the used R and googleVis version and link to Google's Terms of Use.

Warnings

Because of Flash security settings the chart might not work correctly when accessed from a file location in the browser (e.g., file:///c:/webhost/myhost/myviz.html) rather than from a web server URL (e.g. http://www.myhost.com/myviz.html). See the googleVis package vignette and the Macromedia web site (http://www.macromedia.com/support/documentation/en/flashplayer/help/) for more details.

References

Google Geo Map API: https://google-developers.appspot.com/chart/interactive/docs/gallery/geomap.html

Follow the link for Google's data policy.

Note

A map can display a maximum of 400 entries; if your DataTable or DataView holds more than 400 rows, only the first 400 will be shown. The fastest modes are dataMode='regions' with locations specified as ISO codes, and dataMode='markers' with lat/long entries. The slowest mode is dataMode='markers' with a string address.

gvisGeoMap requires Flash, see gvisGeoChart for a geo map based on SVG.

Examples

## Please note that by default the googleVis plot command
## will open a browser window and requires Internet
## connection to display the visualisation.
 
## Regions Example
## The regions style fills entire regions (typically countries) with colors
## corresponding to the values that you assign. Specify the regions style
## by assigning options['dataMode'] = 'regions' in your code.
 
G1 <- gvisGeoMap(Exports, locationvar='Country', numvar='Profit',
                 options=list(dataMode="regions")) 
 
plot(G1)
 
## Markers Example
## The "markers" style displays a circle, sized and colored to indicate
## a value, over the regions that you specify. 
 
G2 <- gvisGeoMap(CityPopularity, locationvar='City', numvar='Popularity',
                 options=list(region='US', height=350, 
                              dataMode='markers',
                              colors='[0xFF8747, 0xFFB581, 0xc06000]'))    
 
plot(G2) 
 
## Example showing US data by state 
 
require(datasets)
states <- data.frame(state.name, state.x77)
 
G3 <- gvisGeoMap(states, "state.name", "Illiteracy",
                 options=list(region="US", dataMode="regions",
         width=600, height=400))
plot(G3) 
 
## Example with latitude and longitude information
## Show Hurricane Andrew (1992) storm track
G4 <- gvisGeoMap(Andrew, locationvar="LatLong", numvar="Speed_kt", 
                   hovervar="Category", 
                       options=list(height=350, region="US", dataMode="markers"))
 
plot(G4) 
 
## World population
WorldPopulation=data.frame(Country=Population$Country, 
               Population.in.millions=round(Population$Population/1e6,0),
               Rank=paste(Population$Country, "Rank:", Population$Rank))
 
G5 <- gvisGeoMap(WorldPopulation, "Country", "Population.in.millions", "Rank", 
                    options=list(dataMode="regions", width=600, height=300))
plot(G5)
 
 
## Not run:
## Plot world wide earth quakes of the last 30 days with magnitude >= 4.0 
library(XML)
## Get earthquake data of the last 30 days
eq <- readHTMLTable(readLines("http://www.iris.edu/seismon/last30.html"),
    colClasses=c("factor", rep("numeric", 4), "factor"))
eq <- eq[[2]] ## extract the eq table
eq$loc=paste(eq$LAT, eq$LON, sep=":") ## create a lat:long location variable
plot(gvisGeoMap(eq, "loc", "MAG","DATE", options=list(dataMode="markers")))
 
 
## The demo 'AnimatedGeoMap' shows how a Geo Map can be animated
## with additional JavaScript. 
## Thanks to Manoj Ananthapadmanabhan and Anand Ramalingam, who
## provided the idea and initial code.
## Please note: This demo requires the package 'pscl' for its data set
## 'presidentalElections'.
 
demo(AnimatedGeoMap)
## End(Not run)

Author(s)

Markus Gesmann markus.gesmann@gmail.com,

Diego de Castillo decastillo@gmail.com

Documentation reproduced from package googleVis, version 0.4.2. License: GPL (>= 2)

Comments

by Joost Keuskamp on Jul 12, 2012

You wrote:

One way of enabling zoom in behavior would be to listen for the regionClick event, change the region property to the appropriate region, and reload the map.

This is exactly the behaviour I would like my map to have. The map displays all countries with a number of markers. I've been experimenting with gvis.listener.jscode but that only seems to triggen an event on clicking a marker, rather than a region. Could you please be as kind as to elaborate a little on how to listen to the regionClick event?