Answer to Map #40
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Answer: This week’s map was an isoline map showing the walking distance from each point in Seattle to the nearest Starbucks.
Seattle, of course, is the city where Starbucks was founded back in 1971. While Seattle isn’t the city with the most Starbucks stores—that distinction falls, curiously enough, to Seoul, South Korea—Seattle is still a place where you don’t have to go very far to find coffee. On average, there is one Starbucks store for every 4,000 residents of Seattle, making Seattle the city with the most Starbucks per capita. In some parts of Seattle, it’s even possible to find one Starbucks across the street from another Starbucks. Why should anybody have to cross the street for coffee?
The idea behind this map was to make something entertaining for the final week of the five-week spring challenge. It didn’t turn out quite as difficult as we had originally hoped, but it did present a nice contrast to our previous isoline maps. Whereas our last isoline map (depicting travel times in Istanbul) had isolines radiating out from a single center, this map had many, many centers all over the map. It’s the same kind of map, but it appears quite different.
Our intention was to draw circles that represented a five-minute walk. We figured out the appropriate size for five-minute isolines by overlaying the Starbucks store locator map with the “How Far Can I Travel” online map tool, assuming people can walk about three miles per hour. This speed may be a little bit generous when you consider that we’re mapping the travel of people who haven’t yet had their morning coffee. Also, we didn’t distinguish between people who walk uphill or downhill, nor did we worry about walking around buildings.
If you answered something akin to “locations of Starbucks stores in Seattle,” then you received only half credit on this week’s map. If we had wanted to map locations, we would have made a dot map, not an isoline map. The distinction is subtle but important. You received full credit if you answered either that the map depicts time or distance to a Starbucks store. You also got half credit if you answered that the map shows distance or travel time to coffee shops without specifying that they are specifically Starbucks stores.
One thing you may have noticed about this map is that there are, generally speaking, more Starbucks locations in the northern part of the city than in the southern part of the city. A vastly oversimplified explanation for this pattern is that the northern part of the city tends to be wealthier than the southern part. It makes sense, of course, that Starbucks would want to be convenient for the sort of person who doesn’t mind shelling out $5 every morning for a latte. But the economics of Starbucks are a little more complicated than that. Research has shown that homes within a quarter mile of a Starbucks tend to appreciate in value more rapidly than homes that are not. Can you make a guess about the cause and effect behind this relationship? What changes might you expect to see in the demographics of a neighborhood where you observed the opening of a new Starbucks?
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