Discussion: How would you map it?

I'm setting a course in a park where a big 'trail' (a dirt road, really) has been closed off by placing dead tree branches across it. It is still possible (for an orienteerer) to run along the edge of the road, but they pose somewhat of an obstacle in places.

How would I map this?

It's clearly a road/trail, but it has obstacles in it that makes it hard to run at full speed. I would say the road is 12-15 feet across.

I'm inclined to change the map symbol to yellow with green lines on top, but I'm looking for advice from seasoned mappers...

(And yes - we are still allowed to use the closed trail and surrounding forest for our race.)

If its that wide and open above, then I agree - go with a narrow strip of open land with undergrowth symbol over it. If its not really open, then perhaps just a linear undergrowth symbol if the brush is fairly continuous. Another option, if the edges are fairly well defined, would be a twin row of distinct veg boundary, with undergrowth in the middle. If its in the woods it doesn't really matter that its a road underneath - to the runner it appears as a linear feature comprised of plant debris (undergrowth).

Can you not simply put some green or undergrowth over the road symbol?

symbol 508 ( small path less distinct ) might be an option , but the increase the size of symbol by editing and make it 200% bigger ( try to see ). symbol 710 ( dangerous area ) could be used as a 1-2 mm width (or as thin that its not becoming a full 'X".) you have to try and play with.

for either symbol i suggest to make a legend "special symbol" describing it in few words.

If its a park map, I'm assuming the scale is 1:4000 or 1:5000. IOF specifies a minimum area for a colour at 0.5mm, ie 2m or 2.5m across, but the symbol for a path is usually only 0.35mm across, so you've got a problem unless you make the path wider.

If you are using 1:10000 or 1:15000 the minimum area for a colour is still 0.5mm, but that represents either 5m or 7.5m on the ground, so you wouldn't really be able to use green. I would use the indistinct track symbol (every 3rd dash omitted).

One option for any scale is to use a green X or circle for 'special vegetation feature', but bear in mind these will take up even more space than a 0.5sqmm of colour. It's possible you could use a small green dot, which is a bit smaller.

For an MTBO map, they use a purple line across the path, representing an obstacle, and perhaps that is one option you could consider.

Finally, which is the fastest route - through the forest or on the path with the obstacles. If it is the forest, then the obstacles definitely need to be shown. If it is the track, then the indistinct track symbol may be the best solution as orienteers will assume this is still faster than the forest.

Can you not simply put some green or undergrowth over the road symbol?

Using this suggestion, it would look like a high speed road through the green or undergrowth.

How many tree branches are there and how frequently do they occur? Are there few enough that you could map them individually?

It's been a long time since I've been there and even longer since it was mapped, but I remember HVO's Silvermine map had a somewhat similar situation. (I'm unaware if that map has ever been updated since the old (80's?) version I've used a few times.)

Somewhere way out there was an old road that was mapped with green over top. I remember the first time I ran on that map spotting this on the map and wondering what it meant. Later on I had the opportunity to find out. It was an ancient road that consisted of lots of pointy rocks that were extremely difficult to run over. Nice handrail, lousy route choice.

Maybe a narrow ride would be the best option, if the road is mostly obscured by branches. The specs say <5m wide without a path. You could then add green spots for particular obstacles and they will show up better over the thin line.

This way, twenty years from now, when real undergrowth starts, you won't have to change the map.

Im liking the open area with green slash option. It doesn't require a special symbol or legend entry and people are used to seeing it to represent overgrown powerline cuts (which sounds a lot like what this is). The main problem with this approach is that if the path is basically north/south, it can be difficult to see the green lines, because you can only fit 1 or 2 of them on the width of the path. In this case, you could go with the option of mapping the obstacles individually (I'd suggest liberal use of the green X) or you could create a special symbol which had the green lines cross-hatched.

Using purple to indicate the obstacles is problematic, because it could be misconstrued as the forbidden route symbol from the Sprint standard.

Jeep trail or dirt road as appropriate with green X's on top of it, maybe bigger than the normal tree symbol. Similar in spirit to the green V's that indicate a plowed and sanded road on a ski-O map.

How about two parallel vegetation boundaries (wide ride) filled with the appropriate green color or green slash?

I agree with the north-south comment above. One of our maps has that problem.

I don't like the idea of using a symbol suggesting 'indistinct', because there's absolutely no way you can cross this trail without noticing it.

So in terms of representing the visibility and runnability accurately, I think the green X's might be the best option.

I haven't tried running the whole trail yet, because when I first saw it there was a sign about some sort of plant disease, and it wasn't until I called the ranger that I realized this is just to keep regular hikers / mountainbikers off the closed trail.

But I think the obstacle density is higher by the trail junctions, which could be represented somehow by the density of green X's.

I mapped a situation like that a few years ago. The trails themselves were distinct enough, but the ends were blocked by downed branches. An example is the trail NE of #9 on this course. Once you're on it, it's fairly fast (or at least was at the time the map was made), but you had to fight through some stuff to get to it. The break between the trails indicates this.

Incidentally, the ISOM standard specifically calls this case out. If the trails actually join, then the dashes should touch on the map. Failing to put a "dash point" at the trail junction is a common novice mapping error and gives the impression that the trail junction is not distinct.