So for as long as they’ve been around, I’ve been a bit fan of Walk Score. It’s usually been just a toy, however as I get ready to move to San Francisco, I’ve been using it to compare against craigslist apartment rentals to the point where I think I’m getting RSI.
So it made sense to clear things up and take a look at the big picture
Read on for how it was done…
Very recently, they posted this amazing map of Seattle which blissfully shows the “big picture”. I was a little disappointed with the level of detail and legibility of the map: heat-maps are good for identifying trends and anomalies, but discrete levels can make it easier to read detail. When it comes to walk score, 2 or 3 blocks can change everything.
I got tired of waiting for them to release these maps for other cities, and decided to spare myself the back and forth between craigslist and walk score by rendering one of these overview maps for San Francisco. Mine certainly doesn’t have the same level of interactivity, but it is highly detailed (to the block).
From here I use processing to create the map overlay. I use bicubic interpolation to determine the value of every pixel on the map, and snap this to my defined discrete levels of color. Snatch some screen grabs of MS maps and photoshop to take care of the rest.
I’m going to be referring to this map quite a bit as I get familiar with San Francisco and hunt for a new place to live. Hopefully this becomes a useful resource for others as well.
Update (July 14, 11:30 PM):
Thanks for the great response! Due to many emails asking for code or the ability to map their own metro, I’ve appended some source code to this post. Download the scraping code. Some description and instructions are included. The mapping code itself is a bit under wraps at the moment, sorry about that. But the magic is essentially Bicubic Interpolation.