1. C REATING FANCY MAPS AND PIE CHARTS USING G OOGLE API CHARTS Lionel Page and Franz Buscha Centre for Employment Research

2. I NTRODUCTION These ado files use Stata’s ability to easily interface with the internet and contact: chart.apis.google.com Google chart API (Application Programming Interface) allows users to dynamically create charts and maps by sending a pre-programmed URL to Google Google then returns a PNG-image which, with a bit of luck, is a useable piece of information!

3. G OOGLE CHARTS API Stata’s unique and powerful data-management abilities make it a good complement in order to pre-format data and then send it to Google and allow it to compile this data into a different array of graphs/figures. How does Google API work? http://chart.apis.google.com/chart? chs=250x100 [size] &chd=t:60,40[data] &cht=p3[type] &chl=Hello|World[labels]

5. GMAP Here we present gmap which allows users to create.png using Google API chart In its current state (v1.1) gmap accepts the following command line: gmap location statevar valuevar {if} [, color(# [#]) graph file(filename)] Width(numlist) Height(numlist)] The parameter location can take the following values: africa, asia, europe, middle_east, south_america, usa, world. For each specific region, statevar must contain the States' identifiers from the list of codes from Google.Google

6. E XAMPLE OF GMAP

7. The following picture will be saved in your local directory gmap usa states value, color(yellow green) graph h(100) w(200)

8. E XAMPLE OF GMAP

9. C ONSIDERATIONS Only have 1 colour gradient at the moment Different shades of one colour Transition from one colour to another Google allows multiple gradients I.e, from green to black to red This ‘should’ allow specific colours across regions E.g. Cons/Labour/Libdems (Blue, Red, Yellow) v.1.2

10. GPIE Here we present gpie which allows users to create 3 dimensional pie charts In its current state (v1.0) gpie accepts the following command line: gpie labelvar valuevar {if} [, color(#) dim2 graph file(filename)]

11. E XAMPLE OF GPIE

12. The following picture will be saved in your local directory:. Alternatively, gpie label values, color(yellow) dim2

13. U SEAGE AND L IMITATIONS Google API charts is aimed at web-based developments such as blogs and websites and therefore offers little in terms statistical analysis gmap should be seen as a informational and explorative tool Limited to 250,000 API calls per day No labels ! Maximum picture size is 440x220 pixels Country labels must be in ISO 3166-1-alpha-2 code Only United States supports state level mapping Please findit tmap (Pisati, 2004, SJ ) for more complicated thematic mapping futures using Stata’s graphics engine