[Talk-us] Best way to tag mile and interpretive markers?
thomas_colson at nps.gov
Wed Jul 24 10:59:41 UTC 2013
Any mile markers we’re adding are monumented, and GPSed IAW with, and exceed, National Map Accuracy Standards.
From: Greg Morgan [mailto:dr.kludge.gm at gmail.com]
Sent: Tuesday, July 23, 2013 9:09 PM
To: talk-us at openstreetmap.org
Subject: Re: [Talk-us] Best way to tag mile and interpretive markers?
Greg Morgan <dr.kludge.gm at gmail.com> wrote:
On Tue, Jul 23, 2013 at 1:12 AM, Martin Koppenhoefer <dieterdreist at gmail.com> wrote:
On 23/lug/2013, at 03:04, Ian Dees <ian.dees at gmail.com> wrote:
> Thomas, I'd caution against placing nodes every mile and tagging them highway=milestone unless there's something more notable about them. Mile markers could be computed from the length of the way
They could but they are not. Another reason not to calculate these is the the freeway exit numbers are tied to mile makers in the US. They pick the closet mile maker to the exit. The exit numbers don't always match up to the exact mile marker location.
and all the extra data might not be useful.
I noted on a trip to San Diego that the mile markers in Arizona switched to call boxes in California. My son and I tried to use keypad mapper to record all the call box numbers for OSM but could not type them fast enough.
In a large city, a mile marker might not be that useful because there are exit numbers. However, if you drive in the wild open middle of the country, then you can go for 10 or more miles before you see an exit number. These are quite useful in that case.
I've also heard that all the Utah DOT engineers live and breath by mile markers. They use 'em to look for deadly areas that need to corrected or other such engineering problems. I wonder if other states use the markers for the same purpose.
Just as when I took a trip and logged all the exits between Phoenix and Flagstaff, I added a couple of refs and exit_to tags on US 60 after a weekend drive. So at mile marker 97 you know that you are half way on the road and the exit_to says power lines. LOL There are also a couple of exit_to makers in Wickenburg too. I understand that using exit_to is a poor choice but it renders. These mile markers are useful on a map because you can use them as an intuitive calculation of when and where you may need to fill up the gas tank.
http://www.openstreetmap.org/?lat=33.962 <http://www.openstreetmap.org/?lat=33.962&lon=-112.825&zoom=11&layers=M> &lon=-112.825&zoom=11&layers=M
I think it's not a problem tagging these as milestones, and there are other people already doing it around here. If there is a particular marker stone I'd use additional tags like historic to underline the significance. You can calculate the length of road segments but maybe they won't corrispond in every case with the exact position of the signs, and as you can see the markers as feature on their own they can also be mapped.
Adding these makers takes some work just like addressing does. The effort to correct survey mistakes makes it difficult to add these milestones, if the cartographers don't show 'em.
As noted above, even though you have a whole mile to type in the marker with something like Keypad Mapper2, I don't know that the GPS on the phone will make the maker location any more accurate than calculating them. Since these markers reset on each road and at state boundaries for something like I15, you'd have to have a GPS point that is created while you are stopped at a marker to accurately calculate the rest of the markers from a known location. For example, I15 starts at 1 in south Utah and finishes either at 401 or 411 at the Idaho border.
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