Register | username: pw: 
Attackpoint - performance and training tools for orienteering athletes

Discussion: very distinguishable trees in woods and brush

in: WPOC - North Park (Sep 10 - McCandless, PA, US)

Apr 21, 2016 5:32 PM # 

Apr 21, 2016 11:19 PM # 
What about small conifer trees?
I think the map would be better without the green x's.
Apr 21, 2016 11:36 PM # 
The ones in the yellow are okay.
Apr 22, 2016 1:16 AM # 
Are those contour lines LiDAR generated by chance?
Apr 24, 2016 12:41 AM # 
They clutter the map, and don't aid in navigation... they should go. I agree with JanetT that the ones in the yellow could stay, but in the white, there are so may so close together, it's hard to see what makes them 'distinct'. And there are plenty of features in the area to use for creating a leg. I could see if you only had one or two, maybe keeping them to use as a control feature for some variety, but otherwise...
Apr 24, 2016 2:18 PM # 
It's not just the trees, there are so many things wrong here...
Apr 25, 2016 6:14 PM # 
Go ahead and start listing possible improvements. Got time to make changes as the meet is in October. This specific location is a former "arboretum" that got overgrown with shrubs and thorny bushes. The large conifer trees with very dark needles do stand-out and are very recognizable: should the green X be removed and replaced with a contour of black dots aka vegetation boundary ?
Apr 25, 2016 8:03 PM # 
Apr 25, 2016 8:31 PM # 
ok, got that as a "bad idea"....
Apr 25, 2016 10:11 PM # 
Mr Wonderful:
Additional people who will attend after you spend 40 hours fixing up maps: 2?
Additional people who will attend if you spend far less time making some ads, posting clever/funny FB statuses with photos, and offering a beginner lesson: 20?
Apr 25, 2016 10:29 PM # 
While I'm hardly an expert, these are my thoughts on specific suggestions:
- The small areas of green on the left of the picture in the semi-open rough ground are below minimum size. When printed, you will not be able to see it clearly enough to have it there in the first place.
- The contours should probably be smoothed out. I'm guessing that when you are running through the terrain you will not be able to notice the tiny little juts in and out that the contours make, so they should be simplified. When they are smoother, they are much easier to read and don't have any false detail.
- A few of your trails also wont be very clear when printed as their line segments are too short.

Other parts of the discussion:
- Take out the green X's in the forest, if you want you can keep them in the open land. Even though they are prominent, they should not be mapped. Imagine if on a sprint map the mapper mapped every lightpost. It is pominent, can be seen from a distance, but there are so many of them that it would just clutter the important information on the map.
- I would also not recommend using the vegeation boundary for the green X.
Apr 26, 2016 12:48 AM # 
The key principle is: Keep only the minimum you need to navigate (at speed) If you can tell where you are without it, you don't need it. The rules out the green x's, the little green patches in the rough yellow. I would consider just mapping the whole thing light or medium green and calling it a day.

And those contour lines can't possibly be field mapped? The kinks look like some sort of noise from some automated data source?
Apr 26, 2016 1:18 AM # 
I can't imagine any good reason for tempting a control setter to use a point feature surrounded by "shrubs and thorny bushes" as a control point. Leave those green X's off the map. The runners will be much happier after the race!

As many have already mentioned, smooth the contour lines (can be done automatically in OCAD by setting the smoothing level on them, which in addition to increasing the legibility will make the file size much smaller when they have been converted to the smoothed Bezier curves instead of little straight-line segments).

Adjust the trail segments by hand, if need be, to make sure that junctions actually connect rather than just missing one another.
Apr 26, 2016 2:35 AM # 
The key principle is: Keep only the minimum you need to navigate (at speed). If you can tell where you are without it, you don't need it.

that's Occam's razor
Apr 26, 2016 2:53 PM # 
Or William of Ockham's razor, with less Latinizing, having lived near Ockham.
Apr 26, 2016 3:06 PM # 
One rule I like for mapping is that an aspect of the terrain should be depicted everywhere it exists, or nowhere. If the tiny jiggles in the contours correspond to actual topography, then equal topography should be mapped when it occurs between contours, or if not feasible (due to legibility or mapping effort), then not mapped at all. Hence the suggestion to smooth the contours. Perhaps a few of the jiggles correspond to mappable ditches, though that'll take substantial field checking to assess consistently across the terrain, and maybe other aspects of the terrain are more worthy of that effort; you'd have to judge based on what seems most navigationally relevant and your time and interest. My 2c, hth.
Apr 26, 2016 4:51 PM # 
I think there are ways to make trails meet nicely. That and the contours are a bigger problem than the green Xs. If this is the most illegible patch of Xs, it might be okay to keep them. But...

These Xs will be of (some, but) little use when navigating outside this zone, only while within the area bounded by the trails and the yellow. So how useful are they, unless you want the course setter to put a control there, which, as Elder said... ? [Depending on the rest of the map, perhaps you do.]

On a 1:1000 map, it is okay to map lampposts.
Apr 26, 2016 5:40 PM # 
Contours: draw your own. Go out with a base map at 2x isoclinedensity and draw what you see. Imagine you are navigating.
Apr 27, 2016 10:43 PM # 
Just catching up.
Re the black dot vegetation boundary option- I've sometimes had JJ's reaction, especially when a mapper tries to highlight conifers in a naturally mixed forest, which is often made too inviting by an orthophoto. I have removed plenty in some situations, because the dots can add more clutter than help.

However sherpes does not have a naturally mixed forest. These trees are cultivated, in an otherwise hardwood forest, and they are described as large and prominent. It's always risky to fieldcheck on the internet, but based on the eyewitness description, it sounds like these trees probably deserve something, within normal O map standards.

I certainly agree with the consensus that there are too many trees for the green X (or O) symbol, but this sounds like a quite normal situation for the black dot symbol, not for the individual trees, but for the main group of nine.

Furthermore, I can only guess at the extent of the canopies, but it appears that the location of the boundary is likely to coincide (~90%) with the existing green vegetation transitions, and based on the description, deserves to be highlighted, more than just a normal runnability transition . The boundary should probably not be drawn next to the trail and road, unless there is a clear setback.

With conifers, the height of the canopy should be a determining factor in their mapping. Low eye level canopies are more likely to be significant. High canopy only? Forget it, orienteers are not looking up, even though these trees may be plain as day on the base material.

And yes, learn to use the multiple curved line drafting tools.The angular green and yellow edges jump at me as much as the noisy contours. I second most of the other drafting suggestions as well.
It looks like you are paying plenty of attention to the details in your fieldwork, which I hope we all want to encourage.
Apr 28, 2016 3:55 AM # 
Contours: draw your own.

From scratch? 99.9% of people would have a hernia.
Apr 28, 2016 1:22 PM # 
btw, the location is 40.594234, -79.992964

Please login to add a message.