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Discussion: Rock Bridge?

in: ebuckley; ebuckley > 2016-04-23

Apr 28, 2016 9:11 PM # 
That's a long way to go for a run???
Apr 29, 2016 12:53 AM # 
Was a target of opportunity. Yaya is on the Dioscean Youth Advisory Council and they were having their meeting out there. I volunteered to drive.
Apr 29, 2016 6:32 PM # 
Nice. There was once talk of making an O map for that park. Do you know if it ever came to anything?
Apr 29, 2016 11:24 PM # 
PTOC has a map of Rockbridge. It is a bit old and wasn't especially good. I think that a bunch of the field checking was done by a MU grad student intern at the state park who wasn't really an orienteer. Dick Luckerman from PTOC may have done some updates, but I haven't seen those.

There is 2009 lidar data for the area. I played around with it a few years ago. I might download it and see what it looks like this weekend.

There are some very old O' maps near Columbia. One at a conservation area called Rudolph Bennett. I think there was also a map at an area called Ashland that was SW of Columbia.
Apr 29, 2016 11:49 PM # 
The park advertises a permanent orienteering course:
Apr 30, 2016 2:02 AM # 
It's actually a very good park for orienteering. Aside from the obvious appeal of the cool rock features around the bridge, there is some really interesting sinkhole terrain in the very southern section. Unfortunately, the 2009 map (which I have a copy of) doesn't do a very good job of representing it.
Apr 30, 2016 1:38 PM # 
I downloaded some lidar and ran karttapullautiin overnight. Here's what it came up with:

The trails, roads and park boundary are from open street map. I'm not sure the vegetation is properly set. There are too many form lines.
May 1, 2016 12:42 AM # 
When I get done with this grad school thing, I'm going to have to catch up on mapmaking technology. I feel like a relic.

That map is not bad, but there is more contour detail in the south part of the park. It would still require field checking. As you said, you could jettison just about all of those form lines.
May 1, 2016 4:12 PM # 
My memory--which could well be wrong--is that Mike Meenehan did the original mapping of Rockbridge, including doing the photogrammetry, which he apparently taught himself while he was at Mizzou. If my memory is correct, I would guess that the map he made was pretty good for the time (early 80s or so) and, somewhat ironically, could well have been a good bit more useful than the typical "modern" maps we get today, which too often suffer from a high degree of over-mapping that results in unfortunate amounts of clutter and illegibility resulting in a map that is harder to use than it should be.
May 1, 2016 9:42 PM # 
there is more contour detail in the south part of the park.

That detail shows up in the data, but the Karttapullautin didn't draw them. They show up clearly in the raw data and the pre-smoothed contours. It'd be pretty easy to add a lot more of the sinkhole contours without any fieldchecking. It might also be possible to tweak some of the Karttapullautin settings to get them to show up.

Mike Meenehan did make an early map. I'd forgotten about that. I think he also did the Rudolph Bennett and Ashland maps. If I remember right, Rudolph Bennett had an unusual contour interval, maybe 6 meters.
May 2, 2016 12:00 AM # 
Haha! I couldn't agree more about overmapping. Of course, that is not a majority view. I gave up as a mapper after the backlash over the Cuivre River map. Some of the criticism was absolutely fair; running the night courses through the areas creamed by storm damage between mapping and the meet was a big mistake. But, the overriding complaint was that the map was, as one US Team member put it, "too 80's" meaning that it wasn't cluttered with a bunch of shit that nobody would ever care about in a park like Cuivre River.

"That reentrant is missing a form line!"
"OK, but you did see the 5-contour spur next to it, right?"
Yeah, but the form line, it's crucial!" How will I know that's the right 5-contour spur without the form line?"
May 2, 2016 2:27 PM # 
It's a quixotic battle, pretty near hopeless in terms of one person (me, anyone else) trying to change in any significant way, and so therefore I have chosen not to waste my time. In some ways it has become almost an ideology that "more detail is better, and even more detail on top of that is even better" and of course ideologies are utterly impervious to reason. Indeed, if anything, the harder you try to argue with facts, the more hardened the ideological believer becomes.

One of my "newer" favorite examples was from the WOC in Italy (though I should point out I may not have the correct facts, so...). A year or two prior to the WOC, a 3 day race was held in WOC relevant terrain, and I believe the maps used became part of the WOC training maps (could be wrong about that.) The maps were all but black with rock detail. Seeing the contours underneath was very difficult, and trying to make out more relevant details such as paths, etc., inside the rock detail was no easier. These maps were just really, really hard to read, and that was indoors, sitting down. But I hadn't been there, I didn't know the terrain, and maybe if I had been the mapper, my maps would have looked largely the same.

Flash forward to the WOC, where what I heard/read somewhere was that on one of the maps--can't remember if it was the Middle or Long--the organizers had ended up removing some *17,000+* rock features (small cliffs, stones, etc.) in order to make the final map more legible. It just makes you shake your head--ha!

Well, perhaps it's all apocryphal, and it didn't really happen that way. Regardless, many of today's maps are really tough to read and, in my opinion, unnecessarily so, reflecting sloppy mapping rather than a professional, discriminating approach that focuses on the major details and making those salient on the map and not submerged in a sea of inconsequential "fly shit".
May 2, 2016 10:31 PM # 
I downloaded some lidar and ran karttapullautiin overnight.

very cool. something that is on my list of things to learn how to do.
May 7, 2016 2:49 PM # 
Cliff Cave:

I wanted to take a look at an area with sinkholes and see if I could get them to show up better than they did at Rockbridge. I decided to try 2.5 meter contours. I think it worked pretty well.

The map is 1:7500 with 2.5 meter contours. Purple contours highlight depressions. Trails and roads are imported from Open Street Map.
May 7, 2016 11:43 PM # 
That looks an awful lot like the Cliff Cave I know. Except, the junked cars aren't mapped.

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