Trees for the wood

[dustytoo]

Looking through my file of urban and sprint maps, I noticed some variation in the use of the tree symbols. The green dot for small trees and the green circle for larger trees is clear enough, but on several maps I noticed that both symbols were used as is, but also sometimes the green dot or green circle was within a small white circle. When I'm running I'm usually too busy to notice niceties, so what is the significance of the white circle?

[MIE]

Looking through my file of urban and sprint maps, I noticed some variation in the use of the tree symbols. The green dot for small trees and the green circle for larger trees is clear enough, but on several maps I noticed that both symbols were used as is, but also sometimes the green dot or green circle was within a small white circle. When I'm running I'm usually too busy to notice niceties, so what is the significance of the white circle?

The ISSOM (sprint/urban) spec. indicates that the "white" outside the green (circle or
dot) is to give the extent of the tree canopy. The larger the white circle the larger the
canopy. Some cartographers don't bother with this

FWIW I map trees as circles or dots based on the "huggabillty" of the tree (i.e.
a dot if I can put my arms around, a circle if not )

In ISOM (standard Omaps) there should not be a white circle outside the green, though
many cartographers cut a white inner to the green circle.

[Angry Haggis]

Extent of tree canopy.

See http://www.soenniksen.dk/sprintkort/trees.htm

(Note, AFAIK it's not formally part of the ISSOM spec.)

[graeme]

"White" is runnable woodland: strictly it would imply the presence of unmapped small trees. Many mappers interpret "under the canopy" as white, it can help to distinguish a big tree from a large bush. In ISSOM I try to only use white to mean "you can run through this as easy as running on grass", with pale green for anything that might slow you down. So everything is about one shade darker on an ISSOM map than in ISOM.

In ISOM the white circle almost invariably means "the mapper can see the canopy on the photo, but not how many trunks there are below, and forgot to note it in fieldwork". ISSOM mappers normally have StreetView available to finesse this.

[andypat]

FWIW I map trees as circles or dots based on the "huggabillty" of the tree (i.e.
a dot if I can put my arms around, a circle if not
.

It would be interesting to see if there was some standard guidance on tree size although dont know of any. Personally I feel that relative size is as good a reason as anything. If there is a group of trees all similar size it's not such a big deal - if one is oboivusly smaller Id use the dot.
My general cut off for dot or circle though is whether or not it looks like I could push it over...

I always thought the "runnable woodland" symbol was inapproapite for use where trees were in grassland. Although it does certainly make it easier to spot trees on the run so has some merit.

[MIE]

Extent of tree canopy.

(Note, AFAIK it's not formally part of the ISSOM spec.)

I stand (or sit ) corrected.

See http://www.soenniksen.dk/sprintkort/trees.htm

I too have (frequently) used these examples to give a guide
when drawing/surveying

[AndyC]

FWIW I map trees as circles or dots based on the "huggabillty" of the tree (i.e.
a dot if I can put my arms around, a circle if not
.

It would be interesting to see if there was some standard guidance on tree size although dont know of any. Personally I feel that relative size is as good a reason as anything. If there is a group of trees all similar size it's not such a big deal - if one is oboivusly smaller Id use the dot.
My general cut off for dot or circle though is whether or not it looks like I could push it over...
.

Now I have long arms so my "huggable tree" is likely to be rather larger and I've seen a few trees that I could have pushed over but couldn't get even my arms round (though the use of different symbols for dead trees is another part of the topic). There is only one relevant criteria IMHO -does it make the map easier to use?

[Wayward-O]

It would be interesting to see if there was some standard guidance on tree size although dont know of any.

ISSOM provides guidance: For symbol 419 (green dot) - Prominent bush or small tree, it specifies the symbol to be used for "A bush or tree with a trunk less than 0.5m diameter." and, by inference, that Symbol 418 (green circle) - Prominent large tree should be greater than this. Maybe the 'hug' test is about right, depending on the length of your arms.

[dustytoo]

Thanks for the replies. What Graeme says about runnability under the trees makes sense, but the size of the tree canopy??? What useful information is that supposed to be conveying to the competitor? What is the point?

[King Penguin]

In ISOM isn't a clearing mapped based on a gap / hole in the canopy above ?
ISSOM mapping the canopy as white seems not inconsistent with this.

[graeme]

What useful information is that supposed to be conveying to the competitor?

That's quite a good question. But remember that white is the default colour, so probably shouldn't be used to convey information. A more interesting question is why the default in ISSOM is "runnable woods".

At WOC this year they filled in the green circles with white. Who knows what that meant!

Personally, I find it useful if the map distinguishes trees from bushes. I'd agree its hardly essential.

[greywolf]

castle and trees.jpg (207.6 KiB) Viewed 5365 times

the white shows the extent of the canopy of the trees (under which it's runnable) or more precisely the yellow shows the open land without trees. The green rings and dots are there to provide control sites

[NeilC]

Thanks for the replies. What Graeme says about runnability under the trees makes sense, but the size of the tree canopy??? What useful information is that supposed to be conveying to the competitor? What is the point?

I'm with you on this. As a mapper I don't bother adding the canopies to a single tree symbol. If the canopy reaches down to the ground making it difficult to run under then I tend to map as a thicket. Many ISSOM maps of course include urban areas and streets with trees on - would you show the canopy in this environment, ie have a white circle cut into pavement under a large tree?

As a competitor a block of white with tree symbols in naturally suggests a wooded area with many trees - some of which are distinctive, not a few big trees with large canopies.

[Red Adder]

It may be in the ISSOM standards but I think using a green dot for a tree is wrong - keep that for a thicket or may be an evergreen where the foliage extends down to the ground (eg a Yew). If the tree is that small that it wouldn't merit a green circle its probably irrelevant anyway.

I actually strongly favour the white tree canopy approach - at large scale it gives a far better impression of the tree cover. I know of a park map with a couple of magnificent chestnut avenues. The first version of the map just gave rows of small green circles which looked pretty pathetic. Later versions showing broad white lines in the yellow works far better.