Looking for a more in-depth view into map projections and indieprojector? Head over to the indiemapper blog to read Andy’s post about working with geographic projections in ActionScript 3. There’s a basic round-up of getting geo-data into Flash with simple projection support and a more detailed discussion about some of the challenges encountered with re-centering and polygon splitting.
It’s a must-read if you’re thinking about rolling your own geographic projection-support in AS3!
If you want to make an omelette, you’re going to have to break some eggs, and if you want to code geographic projections, you’re going to have to bend the world. Here’s a look at the Axis Maps blooper reel courtesy of Cartogrammar developer Andy Woodruff’s blog. Enjoy!
]This isn’t news to everyone, but it’s worth pointing out the fun things one can do with maps using the ActionScript ColorMatrixFilter. Tired of the boring old yellow and orange Google map in the Flash API (or any other map in Flash/Flex)? Lay down a ColorMatrixFilter on that sucker!
The ColorMatrixFilter, if it needs to be pointed out, essentially allows you to mix up the red, green, blue, and alpha channels of vector or raster graphics to produce exciting new colors. Adobe has a nice little article explaining it, along with an interactive demo.
Here’s a little example of simple effects I threw together for Google Maps. Click the links at the bottom for different looks.
I poked around the Google Maps Flash API to find exactly where to apply the filter. If you apply it directly to the Map instance, you’ll color everything, including the Google logo and whatever else floats on top of the map. One level deeper is better, but will still color makers and info windows. A second level deeper is the spot. It’s basically like this, where map is the Map instance:
var a:Sprite = map.getChildAt(1) as Sprite;
var b:Sprite = a.getChildAt(0) as Sprite;
b.filters = [new ColorMatrixFilter([ /* color matrix values */ ])];
In the example above, “Winter” takes the red and green input channels and distributes them equally across all channels, but the blue input remains blue on output. The result is an desaturated, icy-looking blue. “Inverted Grayscale” turns everything to grayscale, but additionally sets the map’s blendMode property to “subtract” and sets it against a white background. That inverts the grayscale image for a somewhat stylish effect.
Now, let’s face it: this is a quick and easy but very limited method for “customizing” a map. (And to be honest, I’m not sure how kosher it is according to the terms of service.) It can make a map look cool, but applying the effect to pre-made tiles means that you’re altering the colors of all features on the map. You can’t keep the official blue and red of interstate highway shields, for example.
So keep this little trick in mind, but be more excited about actual customization (and open data) with CloudMade.
Perhaps the most basic capability of any custom interactive map we make is the ability to pan and zoom the map. That is, after all, the way to make something that might be the size of a wall poster in print fit on a computer screen and still be readable.
On my personal site I have posted a very basic tutorial and example of ActionScript code for a simple version of the way I typically code panning and zooming. If you’re looking for a starting point for panning and zooming, check it out.
Based on my own experiences, if you’re looking for basic ways to improve upon that minimal functionality, consider these:
Tweening zoom changes
Replacing vector graphics with raster while moving the map (faster performance)
Dynamically drawing and placing symbols on the map
Drawing geographic data (shapefiles, kml, etc.) into a pan/zoom map
A few months ago I started on a little side project to visualize presidential campaign speeches spatially. My idea was to collect speeches by the 2008 US presidential candidates, generate a word cloud of the most common words in each, and each word cloud on a map in the location where the speech was given. We’ve seen a number of text visualizations and analyses, sometimes in-depth, during this campaign, but so far not by geography that I can recall. (See those from Martin Krzywinski, and TheNew YorkTimes with help from Many Eyes, for just a few examples.) Are the candidates speaking to different issues in different parts of the country? Are they talking about jobs in Michigan and immigration in New Mexico? Are they pandering to everyone, everywhere they go? (Can we call this project PanderViz?) Visualizing campaign words on a map might answer such questions.
We hoped to develop this idea into a sophisticated interactive map in which a user could search for words, filter speeches by date, and so on. Other work has kept us from doing that before the election next week, but it seems worth showing some screenshots from what I did manage to get done originally.
I went to the official websites of the Obama and McCain campaigns, where the text of speeches is transcribed, and ran the speeches through a simple PHP script to count words and record the location of the speech. This week I revisited the sites to catch up on speeches since the summer. These sources have their drawbacks, of course. For one, although as prepared speeches they contain perhaps the most carefully chosen words for a particular audiences, they do not represent the complete vocabulary used on the campaign trail. Also, Obama’s team has been more diligent in posting speeches, it seems, providing close to 80 speeches since May, compared to about 30 for McCain, a disparity that makes comparison between the two candidates a bit difficult.
As far as I got with the capabilities of this map was generating scale-dependent word clouds (I’ve written more about those on my personal site) and searching for individual words to display proportional symbols representing the frequency of use. With less than a week until election day, we might as well get out of it what we can, so I’ve generated a series of maps of word clouds and individual word frequencies.
The whole series is long—obnoxiously long for a blog page—so it’s at a separate page, linked below. Enjoy, and please comment if there’s an interesting word to look up that I didn’t think of!
