[Talk-us] SPAM-LOW: Re: Rural US: Correcting Original TIGER Imported Ways

Brian May bmay at mapwise.com
Tue Feb 13 01:23:43 UTC 2018


I have spent a very large amount of time cleaning up TIGER in rural 
areas of Florida. I agree with others that the vast majority of 
untouched TIGER ways in un-populated rural areas classified as 
residential are forest roads for logging trucks at best and pure fantasy 
at worst, with tons of barely grass paths all over the place. Many of 
these roads are on private lands that you can't (or shouldn't) access 
anyway. Spatially accuracy is often horrific. I've reviewed a decent 
amount of 2017 TIGER and many areas have not been fixed. The best 
secondary source of data I have found are county streets from the county 
GIS departments, but those vary widely in quality. At the very least the 
county data shows you where all the forest tracks, farms tracks and 
imaginary TIGER streets are, because they are not there in the county 
data sets. Many times, a residential street having no name is a strong 
tip as well that it is not a residential street.

Kevin, I hear where you are coming from, but I think your case is 
somewhat unique. Most people aren't going to look at a GPS with OSM data 
in it, see a bunch of residential roads in a rural un-populated area and 
think, OK, that must be unedited TIGER, but I know there's a few 
navigable roads in there somewhere, I just need to find them, record 
what I found and make some OSM edits. If they know the area, they are 
going to think this data is junk. If they don't know the area and they 
head into it they will then figure out pretty quickly the data is junk. 
I agree with others that these roads should probably not be in OSM at 
all - let the locals add the real roads and tracks. But we are living 
with the old TIGER, and there is some potential usefulness that can come 
from it. So as others have said, we are willing to leave them there, 
downgrade them to track without a grade assigned for now, maybe make 
some spatial corrections, delete roads that are obviously pure fantasy, 
etc.

I don't think there should be any requirement to cover a certain size 
area when reviewing these areas. We need to be thankful that someone has 
taken the time to look at even a small area of rural areas that don't 
get much attention normally at all, especially private lands.

Brian

On 2/12/2018 6:02 PM, Kevin Broderick wrote:
> If you can cover an entire area (which I'd define as a swath between 
> the nearest state highways), I agree that downgrading to track absent 
> other clues is one reasonable solution. One of my key points is that 
> anyone who's spent a fair bit of time trying to use GPS maps (of any 
> origin) in poorly-mapped areas will quickly recognize an area that is 
> clearly an unverified TIGER import, which signals both (a) that the 
> data is clearly questionable and (b) that it might be an interesting 
> place to explore to find out if the roads do go through or not. The 
> questionable map data can be very useful, especially in conjunction 
> with other data sources, in attempting to piece together a route 
> through an area that lacks fully maintained roadways. If a track 
> doesn't actually exist, yes, then it should certainly be deleted, but 
> I've ridden right-of-ways that were damn near impossible to see with 
> leaf-on imagery and also found other routes that looked more road-like 
> via the same imagery impassable, so I definitely wouldn't delete 
> anything unless you can get there in person and look for evidence of a 
> roadway, perhaps one that hasn't been maintained in decades (e.g. 
> Class IV roads in Vermont and Class VI roads in New Hampshire).
>
> Downgrading some ways to tracks without doing so to a whole localized 
> network creates the appearance of a higher level of data accuracy than 
> actually exists, which IMO is more likely to bite someone in the ass 
> than having a localized network of roads that are mislabeled. I know 
> it would make some of the exploring I've done via on/off-road 
> motorcycle more difficult.
>
> I'd also suggest that leaving tiger:reviewed at no is appropriate if 
> you haven't been able to travel the road/track in question and 
> determine whether it is really an unclassified road or a track, so it 
> remains flagged for further review if someone has the time and 
> proximity to do so.
>
> On Mon, Feb 12, 2018 at 3:39 PM, Martijn van Exel <m at rtijn.org 
> <mailto:m at rtijn.org>> wrote:
>
>     I am very happy to see this rekindled interest in TIGER cleanup!
>
>     Having done a fair amount of backcountry exploring, I know that
>     there is a wide range of road grades and aerial imagery alone is
>     not enough to decide how navigable a roads is for a particular
>     type of vehicle. Or, for that matter, what its access limitations
>     are. I do agree with Clifford that leaving them as poorly aligned
>     'residential' roads is the worst possible situation. Yes, worse
>     than deleting the road altogether. What I usually do is mark the
>     road as track without a track grade tag. This seems to me to be
>     the most acceptable generic solution for a remote mapper:
>     acknowledging that something that could potentially be navigated
>     by a 4 wheeled vehicle exists, without being more specific. Local
>     knowledge can then come to the rescue to upgrade to unclassified
>     if appropriate.
>
>     Another note on the MapRoulette side of things: I would very much
>     appreciate your feedback on the new MapRoulette version Clifford
>     linked to. Just email me, join #maproulette on slack, or file an
>     issue at https://github.com/maproulette/maproulette3/issues
>     <https://github.com/maproulette/maproulette3/issues>.
>
>     Martijn
>
>     On Mon, Feb 12, 2018 at 3:08 PM, Kevin Kenny
>     <kevin.b.kenny+osm at gmail.com <mailto:kevin.b.kenny+osm at gmail.com>>
>     wrote:
>
>         On Mon, Feb 12, 2018 at 12:55 PM, Kevin Broderick
>         <ktb at kevinbroderick.com <mailto:ktb at kevinbroderick.com>> wrote:
>
>             Please, please, please don't convert rural roads to tracks
>             based on imagery alone unless it's incredibly clear (and
>             that would exclude anything with forest cover).
>
>             While many of them should definitely be unclassified, not
>             residential, downgrading the main rural routes to tracks
>             doesn't match local usage nor the functional topology of
>             the road network in such places. There are a lot of USFS
>             and BLM roads around here that are the only way to access
>             significant areas, that commonly see normal passenger-car
>             traffic and that can be traveled at reasonable speed in a
>             sedan (or at 30+ MPH with a little ground clearance and
>             driving skill),. Having these differentiated from true
>             tracks (where even a stock 4x4 is likely going to be
>             operating at 15 MPH or less) is incredibly helpful for
>             routing and visual use of the map, and it's a lot easier
>             to recognize what I'd call "areas of questionable data"
>             when they haven't been aggressively armchair-mapped. Also,
>             the smoothness key is really helpful for tracks and
>             impossible to map from orthoimagery.
>
>
>         Yes, yes, yes.
>
>         In the rural areas that I can travel to readily, TIGER is
>         downright hallucinatory (and there are few enough mappers that
>         cleanup has been agonizingly slow). TIGER has roads in places
>         where no road is, ever was, or even ever could be. (I've seen
>         one going up a series of cliffs totalling about 2000 feet of
>         ascent!) But even in 'leaves down' images, it's nearly
>         impossible to see the forest roads, much less trace them, and
>         there is definitely a wide variation in quality. Some of them
>         are well-compacted sand and shale, that once they've been
>         rolled in the spring, support driving at 30+ MPH. Others, I
>         wouldn't bring my Subaru on. (Although I've been on a few of
>         those in the ancient Ford Explorrer that the Subaru
>         replaced.)  Some are gated, some, you simply have to decide
>         for yourself that they're not drivable.
>
>         The 'dirt roads' range from 'highway=path
>         abandoned:highway=track smoothness=impassable' to
>         'highway=tertiary surface=compacted smoothness=intermediate',
>         with no way for an armchair mapper to tell among them.
>
>         The old road maps that they used to give out at gas stations
>         had, on many of these roads, "inquire locally for conditions,"
>         which is still good advice. The signage may say, "LIMITED
>         PURPOSE SEASONAL-USE ROAD: No maintenance November 1-April 15"
>         - but in practice, they'll keep it open later in the Autumn
>         unless the snow comes early, and when they open it in the
>         spring depends on when the crews can get it clear - it could
>         be weeks late if there's been a bad washout or rock slide.
>         There's absolutely no way to tag and encode that sort of
>         thing. Inquire locally for conditions.
>
>
>
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>
>
>
> -- 
> Kevin Broderick
> ktb at kevinbroderick.com <mailto:ktb at kevinbroderick.com>
>
>
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