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Digging in the Astrodirt — Tuesday, May 13, 2003May 13, 2003We lead off this week with another foray into the world of Geography. When I saw a request for maps of the blackout areas for MLB TV, I realized that I wouldn't be worthy of the name Geographer Dan if I didn't at least give it a shot. So let's start with the maps--with apologies to our readers on 56K--and get to the disclaimers afterwards: Hopefully those are pretty straightforward. Each shaded area represents the territory of one or more teams, which are labeled right on the maps.
How The Data Was Mapped The blacked-out ZIP Codes were available on MLB's website here (thanks to Fog City Blues for directing me there). These were matched up with a GIS coverage of ZIP Code Tabulation Areas from the U.S. Census Bureau's 2000 Tiger files. (Whatever your opinion of the Census Bureau, for data-loving geographers, they're the equivalent of Retrosheet or Baseball-Reference.com.) What are ZIP Code Tabulation Areas (ZCTAs)? Well, according to the Census Bureau, ZIP Codes are not simple polygons that cover a certain area. They are actually descriptions of delivery routes that can be approximated as polygons in most places--particularly urban areas. In the rural parts of the country, ZIP Codes are much less coherent. The U.S. Census Bureau created ZCTAs in an attempt to show an approximate polygonal representation of the area included in a ZIP Code. They are not perfect, but they should provide a suitable approximation for this purpose. In some large and sparsely populated areas, the ZIP Codes are difficult to approximate, in which case the Census Bureau used three digit codes--for example, 999XX. Had I left these unassigned, they would leave large empty areas on the map. So I made the questionable decision to assign them the same teams as the five-digit ZIP Codes that began with the same three digits. I can't guarantee that it is the intent of Major League Baseball to include these areas in the blackout areas, but given how complete the resultant coverage is, I strongly suspect these areas should be included. ZCTAs labeled in the form of 999HH, which represent large water features, were treated the same way. Any blank areas remaining on the maps are ZCTAs with ZIP Code numbers that were not included in the listings of any team's territory on MLB's web site. One other problem with filling in the gaps this way: if the first three digits of a ZCTA filled in this way are shared by more than one team's territory, the team assignment between those teams is arbitrary. However, areas with this problem are both rare and small. For more information on ZCTAs, visit the U.S. Census Bureau ZCTA page. And if you have a burning desire for a large, higher-quality version of this map that covers the whole country, e-mail me and I'll see if such a thing is possible. Also, if there are any GIS users around who'd like the coverage/theme/shapefile, feel free to drop me an e-mail. I Meant to Include This Last Week Thanks to Stan Javier for pointing out the Mariner blog Mariner Musings. There's more there than just Mariner coverage, so have a look. Greg "More Plate Appearances Than Pat Borders" Colbrunn Watch Two--count 'em, two--pinch hit appearances. And only one of them was for Ichiro in the ninth inning of a blowout. Colbrunn is tied for second on the Mariners in pinch-hit appearances (two) with Willie Bloomquist, behind John Mabry (ten). While that's still way out of whack, it could be worse. Colbrunn also hit his first Mariner home run on Sunday. Maybe it will inspire more consistent usage. Geography of Baseball Trivia If you drew a vertical line on a map so that fifteen teams were west of the line and fifteen teams were east of the line, what would be the easternmost team on the west side of the line? And the westernmost team on the east side? (In other words, the team closest to the line on each side.) (As always, please do not cheat and look it up.) Song of the Week From the man who brought you "The Real Jim Tracy," here's "Close It Out": Close It Out Look | |||