ISSOM Impassable fences

[greywolf]

No, it's ok, It's not *that* thread (well not, yet, anyway)

I'm mapping an urban area, and as usual there are a number of uncrossable barriers - fence, walls, hedges, which require the usual tweaking and offsetting to accommodate without obscuring all the other detail. It's bad enough with the walls and hedges, but the fence tags can be a nightmare. (some places I'm just cheating and rebadging fences as walls )

Is there any point in having three symbols for "impassable barrier"? why not just roll them all into one and use a thick black line?

[NeilC]

Most of my uncrossable fences have ended up being mapped as "walls" to improve clarity. Sometimes the difference can be marginal anyway from a wire fence, through a solid wooden fence to a brick wall. For navigation purposes distinguishing between hedges and fences/walls can help - but then you have a hedge growing next to fence and what it actually looks like on the ground can vary every few metres.

[Gnitworp]

I think it makes sense to represent a fence shorter than the distance between tags, without tags.

[Spookster]

Fence and wall are both man-made objects, so using the same (black) line seems fine. But a hedge is vegetation, so for navigation purposes it makes more sense for it to be green.

[andypat]

Fence and wall are both man-made objects, so using the same (black) line seems fine. But a hedge is vegetation, so for navigation purposes it makes more sense for it to be green.

It does up to a point, but I'm fairly sure that i've seen events where an uncroassable fence was in fact a tape between canes on the ground, so navigational purposes dont always work. I'd be relatively happy if the next ISSOM update did away with black/green as a not to be crossed feature as it causes so many problems at regular events where the difference between this and regular dark green is hard enough to tell even after the event. Especially when most maps dont have a legend to compare. Its also a nightmare to explain to newcomers as its neither one thing or the other.

[roadrunner]

... the difference between this and regular dark green is hard enough to tell even after the event. Especially when most maps dont have a legend to compare. Its also a nightmare to explain to newcomers as its neither one thing or the other.

I agree with you, but I can't see many newcomers wanting to fight their way through the "legal" dark green, so if they treated both as not to be crossed it would hardly affect their runs.

[graeme]

I used a thick black line for almost everything at Livingston. Only freestanding fences and hedges were mapped as such. Nobody has ever commented.
At the risk of turning it into "that thread" - it might be more useful to have one symbol for "couldn't and shouldn't" uncrossable, and another for "you might not see why, but its forbidden".

[Gnitworp]

it might be more useful to have ................................... another for "you might not see why, but its forbidden".

Purple overprint like ISOM?

[graeme]

For example.

ISSOM is great, and has been a major feature in the explosion of urban races. But now we have five years of experience, surely it's time for a revision?

[Gnitworp]

Yes, ISOM took a good number of years to get 'definitive'.

[Big Jon]

Yes, ISOM took a good number of years to get 'definitive'.

Is it yet definitive?

[dustytoo]

I've recently mapped an area where the slope is so great that the vertical displacement is considerably more than the horizontal. Just using the thick black line to mean an uncrossable boundary - wall/fence/advertising hoarding - was the only way to not obscure vital information - like paths!

I agree that ISSOM badly needs revision - I've never understood why a mapping standard should contain sections essentially to do with organisation (like the stuff about traffic-free areas).