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Mapping

Show Profile  Michael Posted: 22 April 2012, 6:49 PM  
Thanks Ross, its useful to know if most big events are using 1:4000 vs 5000. In urban sprints we have to make barriers and gaps legible to the runner, and that's pretty difficult when a person can get through an 0.5m gap. I note the spec suggests that 1:5000 should be suitable for most maps though.

The olive green that I found hard to see is around control #21 on M21E. The spec doesn't give us a minimum width of a colour, only a minimum area of it. My reading of the spec is that the buildings can be as little as 0.15mm apart, so the olive could comply by area but still be hard to see IMO. Can you tell on RouteGadget which gaps are allowed/not allowed? But as I said its maybe just a senior issue.

Show Profile  rossmaxmo Posted: 22 April 2012, 9:55 PM  
Hey Michael, I took a look, it's really blurry, is it only olive green on the northern part of those 2 buildings?? It looks possibly wide enough to represent as olive, but if there's a path in there as well then it's definitely too narrow.

I think for an impassable area symbol that it needs to be at least as wide as the minimum width of any other impassable feature - 0.40mm I also try to make all area symbols this wide, it says somewhere in ISSOM that they determined that 0.40mm was the minimum size that a runner can read while running, but I think that's very age dependent! So I try to make everything that wide.

One think I discovered early on is the building sizes. If you are drawing them from an aerial photo the actual size of the building (i.e. the walls) is actually smaller than what you see from the picture (i.e. the roof outline). So you should draw them a bit smaller. I think before you draw the buildings you need to check what's in between them to determine the size, the buildings are big and obvious, the size doesn't have to be exact. As has been pointed out, mapping is not an exact science. 0.4mm for an impassable wall is 1.6m wide in real life (at 1:4000). Same goes for an impassable fence. I've yet to see an impassable fence that's more than a few centimetres wide, and if you have a lot of these sort of features close together it makes mapping very difficult - You have to move other things around to represent it clearly, or change the way you map it. Otherwise it's not suitable for sprint orienteering and should be avoided. Another thing that makes life even hard is the gradient. You may remember in nationals last year there was a poolside in Woodford school, very steep with a lot of steps. There was a lot of detail there in a small area, that would have been difficult to map if it was flat, but on a steep slpoe like that, the view you get from the birds eye leaves a really tiny area. I had a few goes at mapping it. In the end I had to map the impassable features first, and then all I could manage after that was the paved edge symbol for the small (but passable) drops. The area could be mapped really well on a smaller scale, 1:1000 perhaps. But when you have an area like that you should avoid putting controls on features within there that don't stand out when the map is printed. (here's where I'm talking about http://1.bp.blogspot.com/-Fb64LEE1P_M/TcKMI1dtEeI/AAAAAAAAAvA/NsopQ1Eny_0/s1600/Woodford%2BIona%2BSprint%2BStandard.jpg)

Anyway, the runner (well at least the top elite) look at a leg and want to see where they can't go, rather than where they can, so those are the most important features to keep in mind, most of the rest is ignored!

Show Profile  Michael Posted: 22 April 2012, 11:50 PM  
Yes. No path in there, I think bushes. I agree the buildings should be shrunk a bit in cases like this, both for the roof overhang and also to make the properties of the gap clearer. I wonder if OCAD could do with a "expand/shrink object about its centroid by x%" function?

Show Profile  Martin Posted: 23 April 2012, 9:51 AM  
"expand/shrink object about its centroid" try using the move parallel feature

Show Profile  Michael Posted: 28 April 2012, 10:25 AM  
Perfect, thanks Martin. Feature has been there for ages too! Invitation to all: post your favourite "OCAD feature that you think might not be widely known".

Show Profile  Paul I Posted: 28 April 2012, 11:34 AM  
That's a clever tool Martin, never used it before but it might be useful in sprint maps.

Some of my favourites...
> "Dashpoint" changing gap possition on a formline (though isn't pefect as it alters many gaps)
> "Sissors" to cut gaps in tracks or contours to make gaps in an exact place when the formline symbol doesn't to a good job.
> "Measure" obvoius tool I find handy if I've noted some distances on my fieldwork. ie; distances of objects from other features or known points on a vague area.
> "Ctrl" button on keyboard, while holding this down you can follow a line with a different symbol, exactly and quickly. ie; two shades of green with no overlap or white gaps, open land or vegetaion matched to track, vegetation boundary to whatever.
> "Change Symbol" one of my more favourite favourites, if I'm altering contours I will usually do all my new changes in blue (stream symbol) so that I know which one's have been corrected and also leaving the old ones there can help. Once finished updating it is then easier to identify where to cut the old contour with the sissors and use the change symbol button to put back to the correct contour symbol.
(interestingly I love seeing contours in blue, for some weird reason I find them clearer)
> "Fill/make border" rather than draw another linear object and to be more precise.

This message was edited by Paul I on 28 April 2012, 1:37 PM

Show Profile  Michael Posted: 28 April 2012, 12:07 PM  
I'm using the dashpoint more and more. I started with MTBO maps with track junctions, they look awful if a side track comes in at a gap, and they can also be ambiguous at indistinct junctions. Then realised they solved the problem of a slope tick on a formline ending up on a gap (especially after a scale change the dashes/gaps move around). And moved on to sharp bends in formlines (reentrants and spurs) which look far better if they are on a dash rather than a gap. They control the ticks on fences too which look odd if they end up at a corner. Lots of uses. Don't really know of a downside, Paul?

Show Profile  Paul I Posted: 28 April 2012, 12:17 PM  
when there are lots and lots and lots of reentrants it struggles to cope, just like a runner.

Here is an interesting link to an experienced ISSOM sprint mapper whith some of his thoughts... http://www.soenniksen.dk/sprintkort/paths.htm

Show Profile  Jason Posted: 29 April 2012, 4:32 PM  
Another OCAD question for the gurus out there: Is there an easy way to enlarge a hole in an area symbol using the cut area or cut hole tool? I get an error message when I try this. Labout-intensive alternatives are to delete the hole and draw it again, or move the individual points defining the shape of the hole.

Show Profile  Michael Posted: 29 April 2012, 6:44 PM  
Mmmm. And any tips to avoid this pitfall? The arrow keys are nifty for fine movement of a selected object. And so my brain expects that having selected a hole the arrow key will move the hole. Nope. It moves the whole object.

Show Profile  Martin Posted: 30 April 2012, 9:18 AM  
Does the move parallel feature work for this Michael?

Show Profile  Iva Posted: 30 April 2012, 10:37 AM  
Measure twice, cut once

Show Profile  Michael Posted: 30 April 2012, 10:46 AM  
The Mmmm above means Mmaybe Mmartin has the answer to Jason's question. When I tried selecting a hole in version 10, the move-parallel button didn't become active.

Show Profile  Michael Posted: 1 May 2012, 10:03 AM  
A scissor feature that I was unaware of for ages: for a linear object you can drag the scissors from one point to another to create a gap. (I used to go cut, cut, select, delete.)

Show Profile  Martin Posted: 1 May 2012, 12:19 PM  
I use this to cut purple lines when course setting - makes it very easy.


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