Discussion: How would you map this?

Raised, wooden mountain bike trail meandering through the woods. A couple on a map I am working one - at least one is relatively long (more than 25 meters). Images here and here

These are bridges and, probably, should be mapped as such.

More importantly, what are these things?!

How about as fences? What scale? At 1:15000, 25m is less than 2mm---perhaps just a black X?

Lots of those in my area, but none that have ended up on O-maps at this stage. They do come and go a fair amount and keep in mind, if they exist, in an area, there will likely be additional trails springing up relatively quickly. A map you'll have to keep on top of. But I do agree with the bridges idea.

Since you wouldn't most likely be ever prompted to run on top of those things, I'd map those as a penetrable building (ISSOM 526.2), with 20% gray infill between 0.07 mm borderlines. If the map is not ISSOM, I would still use the symbol and put it into the legend and mention it as a special symbol.

I'd like to see a picture of a mountain biker riding along one of those. Maybe going off the end into the sandpit?? Or is that the end they got on at??

Are there ramps that are added onto these during mtn biking season?

I'm surprised that people haven't seen these things at all, they are for free riding, or North Shore riding here in Canada,named after the Vancouver north shore.

My MTB friends say you can never really trust them because mountain bikers are notorius for starting and not finishing them, or else taking a "smoke" break during their construction.

Doesn't a bridge have to be bridging something or can it be just a bridge in itself?

Doesn't a bridge in isolation on the map look rather too much like a cliff?

I'll put in my vote for crossable fences. From an orienteer's point of view, they're thin wooden structures that you'd never really want to go on top of. If it were a MTB-O map, that might be a different story. Maybe.

In reply to feet - there "should" be a mapped trail of sorts leading to those bike bridges - would give better perspective on the maps. I'm tempted now to take some pictures of the locals ones and see if folks can figure out how to ride them:-). We've got one called the vortex I believe (it moves, you don't).

I'm with Vlad on this. The ISSOM symbol he mentions captures this best. (ISSOM is designed for this kind of manmade thing, and the mapping quandaries such things provoke.)

Vlad's idea is good, although I think the simplest thing is just to use the black X. The only relevant information to an orienteer is that it's man-made. You could also get away with using Tree Stand as long as you qualified it in the legend.

BTW, these things aren't that hard to actually ride, but they are still crazy because they break so often.

But what are they for? Just thrills, or do they have another purpose?

You ride on them. For example...

If they is a ramp to get on them I think they should be mapped as a bridge, but if they are just there to be there they should be mapped as a crossable building

In some cases there is a ramp angled up to the horizontal part. In other cases because of the slope of the land, the whole thing is horizontal. I may try the bridges idea or just crossable fence. Maybe map it and draw it then see how it looks. I don't think an X would work. When I said 25 metres I think that was an understimate. I think there's one that goes one for quite some ways. I don't think you can see it in the pictures but I think that one actually has a Y junction in it, where two parts join together.

As much as I am generally opposed to it, this might be a case where inventing a special symbol makes some sense. It's unfortunate that the ISOM spec gives special symbols (X and O) for point features, but there's no special symbol for a linear feature.

I struggled with this exact problem last year, making a sprint map in Whistler for the BC Champs in September. Whatever I tried, it didn't feel right. In the end I decided to use a series of black Xs. There is a trail leading to them from both directions.

An orienteer might not understand exactly what this means just by looking at the map, but once they get there I don't think that there can be any doubt that the black Xs indicate the mountain bike "bridge".

How about the (passable) pipeline symbol?



To me it would probably come down to 2 questions: Map Scale, and Whether the thing crossed a ditch or a reentrant making it a valid route choice. The ones at East Fork aren't even on the map yet (as far as I can tell). Most of the ones I've seen are probably X's at 1:10000. I haven't seen any bridges yet, but I'm sure there are some out there.

The symbol on the map should be what the average orienteer's brain will compare it to in the symbol set. LIke that cylindrical concrete flower pot at Fair Hill last fall. It was mapped as a boulder, but if I saw that in the terrain I'd have a black "X" or "O" visualized. These wooden things look like bridges to me. If I ran past one of these in the forest I'd be looking for a bridge symbol on the map. The "passable building" symbol seems less than ideal...I'd be looking for something more like a rectilinear house or awning (something building-like). Lots of black X's is reasonable, but like you say, representing a linear feature with point object symbols is not ideal. A bridge in the forest is unusual, but that is certainly what the feature is. When you run up to it you think thats a bridge. Perhaps an "uncrossable bridge?" :)

Literally, the footbridge symbol comes close, but I think it also implies "ground level" and "passable as a bridge", which this is not, right?

The bigger issue, in my mind, with the 512 footbridge symbol is visual. When drawn (abnormally) to scale, with bends, the footbridge symbol is identical to a tagless cliff, and looks somehat like a small trail or subscale dirt road. In a terrain without cliffs this symbol might stand out as appropriately and uniquely eye catching, but in many/most contexts would not, and would probably be confusing.

The fence symbol seems appropriate visually, and perhaps about the right line weight, but would again be a problem if there are real fences in the area.

For a symbol that I think makes intuitive visal (not literal) sense, I'll suggest something like 515 railroad (visually too heavy?), or 516 power line (visually too weak?). This assumes there are no real ones on the map, a good bet for the railroad symbol. Even with no meet notes, are some people such literal map readers that they would be confused by not seeing the real thing?

If you are philosophically willing to draw your own symbol, I'll suggest using a lightened up version of the railroad symbol, assuming my sense of scale is correct.

For my visual intuition, the ISSOM 526.2 (passable bldg)would work well for a clean, seriously constructed object like the pipeline above, but this bike structure doesn't strike me that way. Granted, this symbol does satisfy the (non)ambiguity issue.

Now that we've spent so much attention on this interesting object, I hope the more basic, but more difficult mapping features, contours and vegetation are done as carefully. :-)

I think that a tramway(515.2) is what should be used It gets the point across and just write in the course setter notes and legend that the symbol is.
It is a 50% black double black line

J-man, you gotta get out more!

If it is ISSOM then what about "passable wall"? (a grey version of impassable wall)
On the plus side it is a "passable" linear feature, and will not look like a cliff or something else. I don't think it would be too misleading in the "wall" respect, kinda like a fence but not quite.

I had a map, which was basically all tiny bike trails, and I used the ski-o green line for these raised bikeways.... not sure if it was a good choice, but I used to have less reservations about making up symbols ;)

You might be right, but I'm inclined to agree more due to the fact that I've read this thread than the fact that I don't know what those things are ;)

The idea of using a ski-o symbol makes me wonder if you should just use a MTB-O symbol, like 816, "Path---difficult to ride." I still like the pipeline symbol due to the similar look (to my eye...).

Not to complain about your map Salal, but I had the hardest time convincing my brain that a green line was a mtn bike bridge and not a hedge when I ran on that map! Green looked too much like dense vegetation. I think so far our best options are bridge (because it is a bridge after all), Magnus's line of black X's (because it is man-made after all) and the elevated pipeline. It is a hard-to-ride mtn bike path, but is it really a path? I think you hvae to pick the symbol that when the runner will get closer to it and see that wood structure in the forest, the symbol that will make him think "what the hell?" the least.

I know, it might not have been the best symbol to use, sorry Barbie... I still think passable wall (a grey line similar to ski-o line) is a good option.