Wednesday, August 12, 2009

Special Use Airspace in Google Earth

According to the FAA, there are 977 U.S. special use airspaces around the world. (Some are international, like the Pacific off of Guam.) By Special Use airspace, I mean the following FAA Types: ALERT AREA, MILITARY OPERATIONS AREA, PROHIBITED AREA, RESTRICTED AREA, WARNING AREA. (Another side note: It's not just the FAA that loves ALL CAPS. The Department State also uses ALL CAPS in its cables.) There are many areas of the United States, in CONUS, Alaska and Hawaii, that are special use.

The FAA flat-fixed file that is the source of this data is so convoluted that I have a new-found respect for companies like Jeppesen that produce the data in a readable format every 56-day cycle. The FAA stuffs 8 different tables into one giant flat file with a well-documented layout.

Google Earth is not perfect with its polygons, either. It's got bugs, especially when it comes to KML stylesheets. I wrote the style tags with VBScript out of SQL, so they are all the same, but in Google Earth, they don't all look the way they're supposed to. It feels like troubleshooting early versions of Netscape and IE when writing HTML. And no, I didn't use some fancy XSL to transform my queries into KML (XML). I used VBScript because it's the tool I know and it's fast.

The usual warning applies: DO NOT USE FOR NAVIGATION. My code isn't perfect, and neither is the FAA's data. There is no substitute for a pre-flight briefing. I ask about the airspace every time flying out of the ADIZ.

Download the file here: US Special Use Airspace.kml.


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