On Jul 27, 2012 8:07 AM, "Alan Mintz" <[email protected]> wrote:
> At least in Region 5 (CA), the roads have N or S in the X position, while trails have E or W. However, I wasn't sure that everyone would necessarily know that, so I went with a more descriptive prefix, based on the terminology Forest Highway/Road/Trail found on the USFS site.
I figured the situation analogous to the Interstate system, where primary routes are always two digits (5 and 8 being 05 and 08) with three-digit interstates starting in odds being spurs and evens as bypasses as being regionally assumed information.
That does not seem to be the case in So Cal. There's a page someone wrote somewhere, outlining some of the methodology. The prefix and letter are loosely related to the township in which a road starts or the range in which a trail starts, but the suffix that follows seems to be just a sequence number. The only forest highway I can think of is SR-39, which is FH-62.
> Road numbers in other USFS forests seem to be largely numeric, sometimes with a letter suffix. Not sure about trails. Most mentions I see are names, not numbers.
One thing that seems to be largely consistent are that highways are two digits, roads are three, and trails are four or more digits, all in the xxyz, where xx is the parent highway (or the primary one it connects to if a road or trail), y is the road and z being the trail number (0 if a direct connection). For example, NFD 4891 is a 4x4 trail connecting to 4x4 trail 4890, which connects to 48.
That's useful. I would still suggest using the different FH/FR/FT prefixes, though, for people who don't know that. Ideally, the map should render the roads differently, too, of course, but they don't always seem to be tagged in a way that allows that.
Alan Mintz <[email protected]>
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