okansas.blogspot.com
Occassional thoughts about orienteering


Thursday, January 20, 2011

Crazy terrain and hyper-detail map

 



This is a fascinating map. The mapper must have been able to draw the vegetation from air photos. Some of the symbols are a bit odd. What are those brown lines near controls 46 and 47? What about the thin black lines along the streams? It looks like a very special, and very interesting, place.

The Google image gives you a sense of the terrain.

Thierry Gueogiou describes is as, "One of my nicest training ever, map super precise with all the single vegetation details - amazing."



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posted by Michael | 7:42 PM

10 comments


Comments:
Who am I to say Thierry is wrong? But my feeling is that all the super precise detail can´t be used in high speed orienteering (maybe Thierry can?), but will probably be nice for a training at slower pace where you have time to spot every single tree. If Thierry reads all this detail at high speed - well, then we have the explanation for his superior O skills.
As for the strange symbols:
* Brown lines ~furrows/trenches? There´s not much to be seen on the aerial photo but that might be it.
* Black lines - no idea really. Before looking at the aerial phot my guess was something like this but there doesn´t seem to be anything like it or anything else either that can be seen in the photo.
 
The first map like this in Spain was this:
http://omaps.worldofo.com/index.php?id=24225
About this kind of maps:
1. Like Tero said is very important a very good mapmaker
2. Map is cool, forest...
3 There a lot terrains like this all arround Spain, is our tipical tarrain
A bad example (Spain too):
http://omaps.worldofo.com/index.php?id=19778

This is my first comment here but I read your blog a lot time ago, specially all about Lidar. Cogratulations and thanks.
 
That is so hard mapping work as useless. Vegetation often looks quite different from the ground perspective. I think this is a bad trend for mapping mediterranean terrain.
I agree Leif. But what Thierry probably do is to select the most singular forms of the green patches. Mortal runners can't read so many details at running speed (and think about the aerial photo at the same time).
If I remember well, brown lines were little and long earth banks. And black lines were small stone walls making terraces along the reentrants. Nice terrain.
 
Thanks for the comments. The ideas about the brown and black lines make sense.

It looks like a really interesting place. I'd like to explore it a bit with the map.

Michael
 
Well, I agree with your comments but when the map is good you can read (o-skill) If the map is... You pratice a new sport: Casino-O. This is usual in Spain about this kind of forest¡?. We want good maps.
See this map, it is from Norway, from Halden:
http://haldensk.no/nyheter/elite/1489-luke-nr-17-hoias-trimtex-night-cup
 
I agree with ALCON.

The challenge is to have a reliable map. As long as the map is homogenous everywhere, it is just about having a good strategy and not about luck anymore.

I am not saying here that it is good or bad to put all the details (even the smallest ones) on the map.
But, for me, the key is to have the same "height selection" on the whole map. So, that after some controls (or the model event for the biggest race), I decide for a suitable strategy and the main details to use.

With Philippe Adamski and Amélie Chataing, we ran this training at competition speed and it was possible to get the controls with a good flow, because the vegetation was trustable (which was not the case of rocks for example) and had many characteristic forms.
 
@ Leif and Luis

Just thinking about what means "high speed orienteering" and "running speed".

Most of time, the speed you used in any type of terrain is limited by your O-skills, isn't it?

Of course, I doubt I will be able to use my best speed in this type of terrain because you are mainly limited by your capacity to process the informations. But just like in Arith (WOC training map) for example.

But does it means that those terrains have to be mapped in a different way?

For me, the answer is that all the terrains have some challenges and the mapping style have to be adapted to it. Our sport is quite versatile and our mapping rules not enough in my opinion.
 
Here I have to agree with Tero that our mapping rules are not enough... I have been and spent time with IOF mapping commision, have heard the discussions there about this problem and they see that. At the same time, in my opinion, they stick too much to map specification with a clearly old origin lets call it so. Even though right now it is version of year 2000 but still says that the o-map is a map in scale of 1:15 000, in some speciffic cases 1:10 000, so any terrain not mapable for scale 1:15 000 is not suitable. Then we would probably loose biggest part of some of the world's most interesting orienteering terrains. Orienteering has changed itself from 1980's or so, and also mapping techniques and people abilities. It is a challenge and our sport is one of the most challenging ones, and so should be our maps!
LieniteG
 
This map reminds me of tnipen's map in this attackpoint thread:
http://www.attackpoint.org/discussionthread.jsp/message_418300

I suspect the mapper didn't map all this in a conventional manner. I suspect he did something like tnipen's manipulation of an aerial photo, or he used some filter on a lidar point cloud.

What is interesting to me is the difference between this map and tnipen's. This map seems to not have the very small points of vegetation.

I wonder for how long these maps will be good? If you didn't have fresh aerials every year or two, you might have to massage the vegetation layers to remove the finest details after the vegetation starts to change.
 
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