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Discussion: Vegetation boundary symbols

in: Runner99; Runner99 > 2018-07-16

Jul 16, 2018 8:05 PM # 
andreais:
Looks like you are using both, the initial and also new vegetation boundary symbol. Have to look at the definitions again when to use one our the other, not sure there is a suggestion. How did you differentiate, choose one over the other?
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Jul 17, 2018 5:41 AM # 
Runner99:
Thanks for the comment! Somebody else told me about it and I started to use it, without knowing much about it. So now i read the ISOM 2017 on it and see that you can only use one or the other on a single map (i'll have to get rid of the black dotted one). I chose the green dashed because a lot of the vegetation that is hashed is obvious and on the ground, and in some spots they are so close that I needed a finer symbol then the black dots to differentiate between the clumps.

Generally the dashed will be better on maps with more rock, or lots of black. Also the minimum size is 4 dashes. Also one isn't allowed to use the dashed around the 2 darkest green area symbols (it is hard to see) but can use 415 distinct cultivation boundary instead.

Jul 20, 2018 2:34 PM # 
andreais:
The other symbol I am puzzled by is the combined use of what appears bear rock plus sandy ground. Although not specifically prohibited, it kind of contradicts itself, as one is solid footing, and the other not.
Jul 20, 2018 9:51 PM # 
mikeminium:
Bare rock plus stony ground? Maybe a solid slab with a covering of loose scree? Can't say that I've seen that mapping combination before but it might kind of make sense...
Jul 20, 2018 10:27 PM # 
andreais:
@mikeminium stony ground used to be random dot pattern, but I guess you are right, the 3 new symbols (varying density) are more orderly. I just checked, the sand symbol gets completely covered by bare rock, no dots visible.
The reason why you may not have seen it is because the documentation states
"A runnable area of rock without earth or vegetation should be shown as bare rock.
An area of rock covered with grass, moss or other low vegetation, shall not be shown
using the bare rock symbol.
An area of less runnable bare rock should be shown using a stony ground symbol
(210-212)."

Bare rock is considered runable (I thus think 100% or not much less, whereas stony ground represents reduced runability (60-80%). The 2 symbols used together thus contradict one another.
Jul 21, 2018 8:23 AM # 
Runner99:
So that's actually sandy ground on top of bare rock. Because in those areas there's alot of obvious gravel that's almost 100% fast. I changed it to pavement (brown) because after talking to someone here in Europe they said they use the pavement symbol for any hard surface.

The bigger reason for the bare rock was because it was clearer than the pavement, you could see the edges of the area. I had the sandy ground / stony ground too because under the canopies you can't see the pavement. And I think bare rock covered the trees so that wasn't optimal either.

Jul 21, 2018 4:48 PM # 
mikeminium:
Against the surrounding yellow, I think the bare rock symbol stands out much more than pavement. I think I'd stay with the bare rock rather than pavement. A light coating of sand that does not slow runnability is probably irrelevant, and I'd just leave off the sand. On the other hand, if there is enough sand that makes it hard to distinguish the bare rock from surrounding open land, then maybe showing the rock at all is over-mapping? That's my take, not having actually been in the terrain to look at the specific situation.

To show single trees over bare rock, I think you can create a new "green" color that will show over the grey (like tree symbols that show over pavement) and a second tree symbol using that color. Andrea might know if there's anything in the new ISOM that says you can't do that - I haven't used it that much yet.
Jul 21, 2018 5:54 PM # 
andreais:
What I understand from one of the guys who has been on mapping commissions is that you should not mix symbols. that give you conflicting information about runability. Also, pavement, whether graveled or actually paved is technically a manmade thing, and a runner would expect something of that nature, and not bare earth that happened by nature. It would be overmapping an open yellow. If theedge is natural and not man made one should also not use the pavement edge as I understood it.
As Mike says, duplicate the tree symbol, duplicate the color used an move the new green up to be above the bare rock grey, and then edit the new tree symbol and assign the new green, which is identical in shade and hue with the original tree symbol, but shows up on grey.
Join the o-map (or mapper) yahoo group and ask questions there. There are some really good mappers, especially also some who have worked on the standards, who give really good answers and reasoning.
The other lesson I learned is to forget what I know and saw when drafting, and look at the map and ask myself what would I expect to see as a runner, and what I would imagine runability first and visibility secondarily to be.
Hope this makes sense.
Jul 22, 2018 2:02 AM # 
Canadian:
Note that the sand/gravel symbol signifies that it significantly affects runnability. If it's hard packed enough that it does really slow you down (I.e. you'd never bother taking a route choice around) then don't map it (at least not with that symbol).

In general, as a mapper your goal should be to put as little as possible on the map while still enabling the orienteer to navigate at race pace.
Jul 23, 2018 8:07 PM # 
Runner99:
@mikeminuim I'll visit the map and see if the bare rock or the pavement color fits more depending on how obvious the rocky ground is. I'll also see if there is any purpose for the sandy / rocky ground.

Thanks alot for the feed back!!
Jul 23, 2018 8:11 PM # 
Runner99:
@andreais the only reason that I have the two symbols mixed is because it makes it clearer to see the edges. Its probably overmapped so I'll look at simplifying it....

I'll play around with the layering of the trees as you and mike said.

Everything I put on a map is intended for navigation while one is running, so I just need to verify that it is obvious enough. Its kind of like scandinavian marshes, some are kinda indistinct but still mapped because they are obvious enough

Thanks for the info!!!
Jul 23, 2018 8:19 PM # 
Runner99:
@Canadian I'll probably take the sand / rocky ground symbol off due to this... I think of it kind of like when there is a marsh in a clearing. If its dried up it can often be fast and is more of a navigational feature, and even when its wet it doesn't slow you down significantly unless its at least ankle deep

The reason I want to keep it in, is because alot of the trees look the same and can't be used for navigation at high speeds. So one is effectively stuck on a bearing with no plan except crossing a path occasionally. If i can somehow map the sandy ground then people can use it as a feature on their bearing, and actually have a better plan.

Thanks for the input Jeff!!

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