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Discussion: Mapping vegetation ovjects in green(ish) areas

in: Orienteering; General

Oct 5, 2019 7:07 PM # 
I was recently involved in updating a map for the Teanaway Cup (see and for routegadget) and come to think about what would be the best practice to put various vegetation objects on a "noisy" background. As a context, the terrain is largely open forest but contains many smaller cops of vegetation of various degrees of green, and in places it is steep. So there are lots of contours and green.

Here are three ways to add a tree and a rootstock onto a complex area:
What is your opinion about the best approach? My favorite is #3, the one with gaps in contours, but I don't think I have seen any map where one does like this. Thoughts?

(The example taken from
Oct 5, 2019 7:20 PM # 
That seems to be taken care of rather nicely by the new white mask under the green x and o, see ISOM 2017-2.
Oct 5, 2019 8:02 PM # 
Thanks, andreais, was not aware of that. So this issue will probably go away when updating the symbols.
Oct 5, 2019 11:45 PM # 
I am not a fan of mapping rootstocks, one windy day and there are a whole lot more of them, but it is also common to use 115 prominent landform to map them. Often there is fair amount of dirt on the roots - making them arguably a 'landform'. In Australian orienteering they are generally called 'rootmounds'.

Until recently the symbol was a brown cross but it has been changed to a brown triangle. That will show up much better than a green cross. You will need to make a gap in contours if the triangle touches or crosses them, as you should for other brown symbols like small depressions.
Oct 6, 2019 8:08 AM # 
I'm not a fan of mapping point features within green areas, since some course planner or other will eventually put a control there to the annoyance and frustration of a majority of competitors. And I'm curious as to why you would map an individual tree in the forest (white), let alone in a green area, and as to why ISOM would appear to sanction this.

I agree with Rob about using the brown triangle for rootstocks - if they have to be mapped at all (I prefer not).
Oct 6, 2019 8:16 AM # 
I wasn't sure if mapping trees in green was a thing so didn't initially comment but I'd be pretty upset if I had to find one.

I think there's (at least) one map in NSW that has individual cherry trees mapped in white because they're kind of distinct, unless you don't know what you're looking for. Juffy's Jumbuck Hill map also had that great big white gum mapped in white because it stuck out but the remap by Alex Tarr got rid of it.
Oct 6, 2019 8:41 AM # 
Over my years orienteering in ACT, NSW and Vic I must have had at least 50 controls on native cherry trees, but I still don't know what they look like, or how they differ from all the other trees in those Dividing Range forests.
Oct 6, 2019 8:44 AM # 
or snotty gobbles in WA that were on my first O event in WA, amazing that I came back after that experience
Oct 6, 2019 10:23 AM # 
Can't have been as bad as a left handed blackboy (a rogaine control description from back-in-the-day).
Oct 6, 2019 10:56 AM # 
Just in case anyone (particularly on the other side of the Pacific) gets outraged, "blackboy" was the name given to a particular type of plant (more properly known as Xanthorrhoea). The old common name is gradually falling out of use in the last decade, but still turns up here and there.
Oct 6, 2019 11:23 AM # 
If you have the luxury of predominantly white and some light green forest... But if your forest are increasingly "eaten" up by species that render your maps from predominantly white 15 years ago to predominantly dark green maps now, and many of your participants still like going into the forest rather than be restricted to the trails and little white or yellow left anywhere, why remove features you know are still there.
And then there are places like the tropics or equator, like Taiwan or Singapore, with either nicely mowed parks or lush rainforest and not much in between; with paved or cobble stone trails in the dark green cause vegetation would eat up the trails in no time. Example of trees that are very distinct: a palm tree, straight distinct trunk in the middle of deciduous with knarly trunks, off trail, but can be navigated to.
Given the mapping standards, there is also no real alternative for trails in dark green like the ones in the Asian tropics often marked by ribbons on trees put by people because the footprint of the trail goes away as vegetation quickly erases it even if used weekly or daily. Based on isom it does not even qualify as an indistinct trail, but also not as marked route because it is not consistently marked.
Oct 6, 2019 10:54 PM # 
I'm not a fan of mapping point features within green areas
I have heard this sort thing a few times. It is the mapper's job to make a complete and accurate map. If there is a a valid point feature in green it should be mapped just like any other valid point feature. It is not the mapper's job to anticipate courses and certainly not to try to second guess bad course setters. If I started trying to do that I would soon end up with completely blank map,
Oct 7, 2019 9:45 AM # 
Terje Mathisen:
@robplow: As you say, the map should be the best we can make with the available time/money budget, and that includes mapping objects that are hard to see.

OTOH, course planners should almost certainly avoid using such features for controls! My "favorite" example is even worse, i.e. controls that are extremely hard to spot when you get there alone, but dead easy if there is a runner already there.

I.e. flat open plain with a 1m hole and the flag down inside: With a runner punching the control is obvious from far away, otherwise you can spend a minute or two pacing and trying to hit it.
Nov 27, 2019 3:39 AM # 
I agree that the course setter should avoid using any objects buried in medium or dark green areas. Sometimes, however, the feature, as mapped, overlaps the edge of a green area, and would be obscured if we didn't mask out the green (and sometimes yellow) areas.

The most obvious example is a giant lone pine in an area of deciduous shrubs. It can be seen from some distance away, and might be on the edge of a thicket.

Here in Illinois, we suffer from a dearth of navigable objects in our woods, and an abundance of undergrowth. For many years, our mappers would include all distinct rootstocks (brown Xs at the time). Of course, after just a few years, many of the old rootstocks would have rotted away, and new trees might have fallen, leading to the situation where course setters and participants learned to ignore the rootstocks, which defeats the purpose of mapping them.

Starting about 10 years ago, we set the standard that rootstocks would only be mapped if there were roots raised at least 2 m off the ground. These largest of rootstocks could be expected to last for many more years, and would be less often mistaken for your run-of-the-mill fallen tree.

Also about 10 years ago, we noticed that many of the fallen trees and rootstocks included very distinct trunks and canopies that could be mapped so that the competitors could use their orientation and length for navigation. Controls could be placed to make it more likely that the feature would be seen before the control flag, which is usually more fun.

Of course, ISOM doesn't include distinct trunks for either fallen trees or rootstocks. So, we had to make our own symbol.

Here is the results, from OOM 0.9.0, which also includes the white mask under the distinct tree and fallen tree symbols. I modified the symbols to include the stem, and the underlying white mask for the roostock symbol.

As you can see, the white mask covers contour lines, form lines, and both green and yellow areas. It also covers paved areas and undergrowth symbols, but this is not shown in the example. Notice, too, that the distinct bush symbol has been updated to include a tiny white dot in the center to make it stand out a little more.

If anyone would like a copy of the symbol definitions, please let me know. The color scheme is a little more complicated than normal, as there are now 2 Browns ("Brown 100%" for contour lines and "Top Brown" for the rootstock over the white mask) and 2 Greens (the regular green between yellow and blue, and a "Green 100%" above the white mask above the regular colors).

I'd love to see the trunk option added to both the green X and brown triangle symbol in the ISOM, but I don't want to deal with the politics of the mapping committee. ;)

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