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Mapping

Show Profile  Paul I Posted: 13 July 2013, 10:25 AM  
Seems wrong to me to leave off the mounds if they are distinct. I would think any significant ones would stand out as much as some knolls and rocks, if not more than.
Generalisation of rock to only the big one's can totally depend upon the terrain. With the undergrowth and moss covered rocks shown on the tv coverage small rock wouldn't stand out well in the terrain hence a higher level of generalisation. I am certain this level would be reduced if the forest floor was clean. So it's all relative with no fixed rule. Mappers discretion rules sometimes.

More of a topical discussion would be around the overuse of formlines, Long and Middle, especially for a WOC map under IOF scrutiny. They were happy to bag France about their mapping.

Show Profile  Michael Posted: 13 July 2013, 11:54 AM  
On a philosophical level, we include distinct point features that have the right density. When there are too many (a) we can't fit them in and (b) they are no use for nav anyway. Silly example, trees in a forest. More pertinent example, rock features, termite mounds. You're right it depends, we would have to be there to judge.

Yes I've often felt a clean forest floor brings problems. It makes all features (incl contour wiggles) much more distinct. And then there become too many, see above. I think the blueberry ground cover, fallen trees, young saplings etc that we saw, may make the generalisation easier. Including the contours, the number of formlines is surprising. Possibly its the "LiDAR effect" that has been talked about at mapping conferences - if its on the basemap, its actually very time-consuming to decide which to smooth out. You can even get this on Stuart Hyslop photogrammetry when he has good photos.

They usually have a mapping conference at WOCs. I don't recall seeing any proceedings from France or Switzerland. We should ask.



Show Profile  Kenny Posted: 14 July 2013, 10:49 PM  
G'day

I see that LINZ is making 85% of aerial photography free access. Curious as to whether you know yet whether that is likely to be useful to you or do you have other sources these days?

Ken Dowling

Show Profile  onemanfanclub Posted: 15 July 2013, 8:37 AM  
I can't help bringing a bit of bio-pedantry to the brown cross part of the conversattion. I'm assuming these were ant hills rather than termite mounds. These can get as big as the sort of knolls that we'd expect to see mapped in eg sand dune terrain, so in that repsect I can understand them being mapped, but rather than the big "clay-brick" towers that the Aussies and kiwis would expect to see, I'm guessing they would look more like a mound of whatever the typical leaf-litter/forest floor material is. So from an Australasian orienteer's perspective I can well imagine it would have taken a bit of adjusting to. Hopefully they were present and mapped in the model areas and training maps.

Show Profile  Michael Posted: 15 July 2013, 1:34 PM  
Ken, there has been a "club" of mainly govt organisations that has been sharing imagery (the KiwiImage program), and they have now handed this project to LINZ to release on a creative commons basis for the public good. The KiwiImage std I think is 0.6m pixel size and where local authorities have contributed it is smaller, this will be pretty useful. The coverage is shown here: http://www.linz.govt.nz/topography/aerial-images/creative-commons-licenced-imagery

Up till now (and probably still useful until LINZ completes its processing work) methods we have been using include: purchase from aerial mapping companies, buddy-buddy arrangements with councils and other organisations, NZTA has most of the state highway network covered (about a 1km swathe), and the Walking Access Commission has pretty much the whole country covered by www.wams.org.nz.

Show Profile  Michael Posted: 16 August 2013, 9:32 AM  
I made this comment to another mapper in discussing generalisation, wonder what others think. Specially anyone who ran on both these maps.

Interesting to compare the approaches at JWOC in Czech and WOC in Finland (middle distance maps I think). As I recall in JWOC they used a lot of stony ground dots and I found it hard to make out the boulders on the map. In WOC they didnt use stony ground, the map looked very clear and they even had enough white space for some vege boundary dots. But Malcolm (Ingham) commented that only the big rock was mapped. I wonder which was easiest to navigate in? The map that had everything on it but was hard to read, or the map that had less on it but some people expected more?

Show Profile  nh Posted: 16 August 2013, 3:25 PM  
I found the WOC maps easier to read than the JWOC middle maps. But the rock on each of the terrains was very different. The JWOC rock was all broken and more like a boulder field, but the Finnish rock was more like bedrock poking out of the ground

Show Profile  fraser Posted: 23 August 2013, 10:07 AM  
OpenOrienteering wants ideas for its Android app.
http://oorienteering.sourceforge.net/?p=173

It seems like you could avoid a lot of double handling if you can do the fieldwork directly on a tablet or other mobile device.

Show Profile  Jamie Posted: 23 August 2013, 7:06 PM  
Man, I'm so going to take up mapping when you can draw the map straight onto a tablet


Show Profile  rossmaxmo Posted: 24 August 2013, 4:48 AM  
That has been possible for a while Jamie - time to get started

Show Profile  rossmaxmo Posted: 23 October 2013, 2:07 AM  
Interesting discussion:
http://news.worldofo.com/2013/10/20/sandvik-after-25manna-we-need-good-legible-maps/

Show Profile  Selwyn Posted: 6 November 2013, 5:30 PM  
Thanks for the link rossmaxmo. To me, it's reassuring that the rest of the orienteering world is debating the same issues that are concerning us in NZ with respect to IOF's ISOM revision.

Show Profile  Paul I Posted: 6 November 2013, 7:21 PM  
but I don't think anyone's listening Selwyn.

Unless there is some kind of compromise on the MC 1:15000 sway, then I believe we should consider making two versions of our most appropriate maps. A long distance version with more generalisation for a 1:15000 scale, and the status quo version 1:10000/1:7500 for middle events and the like.
This goes against one of the arguments for 1:15000 of trying to keep costs down, but at the same time allows us to fit better to the IOF MC agenda more easily. It may also give us some new life to tired or over used terrain.
My ultimate fantasy would be to allow for a 1:12500 scale to be used for Long Distance, as they do with Ski O. But I appear to be a lone ranger on this one
I don't believe that the map scale itself is so important but legibility/levels of generalisation that still allows for detailed areas to make sense.

Show Profile  rossmaxmo Posted: 7 November 2013, 3:34 AM  
I guess eventually we'll just end up running with some kind of lightweight tablet strapped to our hand with a dynamic scale.. but still there will be the issue of deciding what level of detail needs to be shown/omitted for fast-paced orienteering - I think it should vary depending on the terrain type - I understand the need for the rules for some sort of normalization, but they can be quite restricting and for some terrain types, plain annoying. I guess as far as scale goes, I really don't mind what it is - anything is fine for me 1:3000 to 1:15000, as long as I am able to extract the important things from the map without being overwhelmed by insignificant detail whilst I'm running...

Show Profile  Michael Posted: 7 November 2013, 1:09 PM  
For sure there are fascinating terrains with lots of detail, and we seek them out and enjoy them. Equally for sure there are sub-1m "knolls" on maps and ankle-deep "depressions". And (a bit harder to deal with) photogrammetry and Lidar with wiggles that take several minutes standing still to identify on the ground. We CAN generalise better.

But that's separate from what has happened with the ISOM revision. Nothing on the IOF website.


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