Last week, Yahoo! released a new service called Placemaker. Developers can use this to identify location information within unstructured content. Send Placemaker a bunch of text or a URL to a web page and it will return back a list of places referenced in that text or document.
“Placemaker is not a geocoder and does not perform street-level address recognition; it is however a geo-extraction and indexing tool designed to help determine the ‘whereness’ of a document or atomic unit of text. It provides the geographic developer community with the means to mark-up and index their content geographically in a globally-aware, locally-relevant, and language-neutral manner, and assists with geographic discovery and aggregation across the Internet.”
Send Placemaker the text “San Francisco” and you get back the city, state, Where on Earth ID and latitude/longitude. Feed the service a web page, like the CNN.com homepage and you get back a list of all places found on that page. Now, just to clarify, the locations returned by Placemaker are not addresses, but cities, states, countries and points of interest like parks, schools and landmarks.
I found this to be a fascinating concept. What could this service do for me? What could I build as a way to test the power of Placemaker? Well, a couple days later I am introducing a working version of mapZING.
About mapZING
mapZING is an incredibly small prototype that injects itself into any web page. A little window displays on top of the page’s content with a map marking all of the places found. Here’s a screenshot of the app on top of the CNN homepage.

How does it work? Simply add this mapZING link to your browser by dragging it to the toolbar or by right-clicking and saving as a bookmark/favorite. Next, go to a web page that has some location info on it. Good candidates I found are news sites, the Wikipedia homepage and local sites like for my home town.
The White House is pretty good too!

How to use mapZING
- Drag this mapZING link to the bookmarks/links toolbar or right-click and save as a bookmark/favorite.
- Go to a web page with location information.
- Click on the mapZING bookmark to all of that page’s places on a map
Note that large web pages (over about 50,000 characters) are not allowed to sue the Yahoo! Placemaker service and there’s a surprisingly large number of pages that you’ll find rejected for this reason. I found in my testing that size was the most likely problem.
How I built it
Over the course of just a few days, poking at this idea when I had time, I was able to build a small working prototype app. There’s a lot of clean up to do and improvements I’d like to add. You can read more about the code behind mapZING in detail. I wanted to expose all of my code to 1) force me to do a better job 2) be humble about about my work and 3) allow others to learn where possible.
Like it? Hate it? Found a bug? Have ideas for improvements? Let me know in the comments!
Why the name? I didn’t want to create “Dan’s mappy bookmarklet thingy” so I turned to a web search for uncommon map-related names. It turns out that mapzing is pretty uncommon, so I took it. Silly, but unique!
In case you are testing mapZING on this page, here’s some place data:
- San Francisco
- San Ramon
- Coit Tower
- Golden Gate Bridge
- Oakland
- San Jose County
- Powell Street Station
- UC Berkeley

[...] Our amazing Dan Harrelson harnesses Yahoo’s Placemaker to create mapZING. [...]