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Mapping

Show Profile  MikeB Posted: 18 April 2013, 6:46 PM  
Mike don't you ever sleep?

Show Profile  Michael Posted: 18 April 2013, 7:54 PM  
Mike compare the Maptalk clock with the one one your wrist.

Show Profile  Michael Posted: 7 May 2013, 3:13 PM  
Years ago Svend suggested the 4-colour Bic for fieldwork. Works fine, WHEN its fine. But I've just found the answer for damp conditions. Try Inkjoy. Cheap as chips, well I haven't done an endurance comparison but at under $1 each its not an issue. I've found black, blue and red but not green. Rubs out with the typists eraser I use. (Typists. Remember them?)

Show Profile  Michael Posted: 4 June 2013, 11:12 AM  
Martin used Pullautin to generate the basemap from raw LIDAR data for yesterday's map "Bombay Quarry". A fairly straightforward spur-gully area but nevertheless this is a significant achievement. (Jason I think you were generating contours from the raw data at Teetotal but perhaps not inferring vegetation differences from the treetop reflections?)

Show Profile  Michael Posted: 4 June 2013, 3:28 PM  
The Inkjoy has exceeded expectations, not only writing on dewy tracing film but also when there is water on the surface. I have found you can get a box of assorted colours - includes green but as its not a very intense colour I may use the magenta or the purple for vegetation boundaries and codes. The box of 12 was the massive sum of $7.82.

Show Profile  Rog Posted: 6 June 2013, 11:13 AM  
http://t.co/x8fAPBmv5D
Presentation by Helge Gisholt: Sprint map experience and representation in city urban area - Miscellaneous Challenges
Map Meeting Skien, 25-May 26 2013
(via Twitter from Eva Jurenikova @evajurenikova)

To get a better understanding of content, try Google translate.

Show Profile  Michael Posted: 12 June 2013, 8:56 AM  
There's a draft of a new ISOM out for comment. The technical committee has sent it to a list of mappers, and Selwyn has undertaken to coordinate a NZ response. Discussion is going on by email, if you're not on the list ask Greg or Selwyn. I suggest that we NOT use this thread for comment but carry on by email. If you just want a look, go to http://www.orientering.no/SiteCollectionDocuments/ISOMrevisionFirstDraft201305.pdf

Show Profile  Michael Posted: 3 July 2013, 11:08 AM  
Selwyn has coordinated a response. In summary 1. After 5 years deliberation by IOf, 5 weeks isn't enough time to properly consider it 2. Disappointment that the obviously popular trend towards more detailed terrain isn't recognised, and there is no real help for those of us using digital printing 3. Concern about the benefits vs effort of an additional runnability level, and about declaring hard-to-cross features as out of bounds. We asked for 5 months to consider the large number of more detailed changes in the proposal.

Show Profile  Michael Posted: 3 July 2013, 11:15 AM  
The maps on the JWOC website use relief shading. I think that's just for us viewers, but I wonder whether we should do this for competition. "Seeing" ground shape from contours is a peculiar skill that some people have difficulty with.

Show Profile  hughff Posted: 3 July 2013, 7:57 PM  
I think the relief shading is great when the light source is good. I guess the question is whether being able to read contours is one of the essential map skills that would be lost if race maps were changed. I'm reluctant to change but I'd be interested to hear other views.

Show Profile  The Map Guy Posted: 4 July 2013, 12:22 AM  
Relief shading only works well if the map is viewed from the bottom. Free 15m contour DEM data is available from Ko-ordinates and can be used to generate Relief Shading. The resulting TIFF file is a Raster image and at 1:10,000 scale would show extensive pixellation.

Has anyone else got an alternation source of high resolution DEM data (hopefully free?

I've successfully produced many maps with relief shading but they have been at 1:30k, 1:50k and 1:60k scales

Show Profile  The Map Guy Posted: 4 July 2013, 12:24 AM  
Should read: Has anyone else got an alternative source of high resolution DEM data (hopefully free}?

Show Profile  Selwyn Posted: 6 July 2013, 9:42 AM  
Auckland Council has supplied me with DEM data on request. It has taken a bit of pestering as I suspect it's low priority. It seems that for them it's easier to supply it as whole map tiles, for rural areas about 7.25km x 4.8km. The last request came as two tiles together and involved about 48 million points, but half of one was ocean.
That suggests that the elevation samples are approximately 1.5m apart.
OCAD11 Standard supposedly has a maximum processing of 30 mill points, but OCAD went ahead and created contours anyway.
Although the data supplied did include all the Lidar responses, at this stage I have only had time to deal with last response, ground level contours. In Woodhill the orthophotos are usually perfectly adequate for determining vegetation changes.
The OCAD generated contours are considerably more precise and detailed than the 1m contours that are available on the Council web site. The Council website gives 1m contours in rural areas. With OCAD generating the contours from DEM I can request 2.5m as well as 1m 5m or whatever. If you use OCAD Professional to generated contours from the Council Shape files they supply 1m intervals, so generating 2.5m is not an option.
There are still some small areas of major flaws where e.g. a depression 25m x 15m and about 5m deep just got recognised as part of hillside.
Having everything nicely georeferenced means the GPS is very useful for confirming where I am with respect to the orthophotos and/or contour data which doesn't have slope lines or contour elevation tags.

This message was edited by Selwyn on 6 July 2013, 10:51 AM

Show Profile  Michael Posted: 12 July 2013, 11:30 AM  
Interesting to see what we can learn from the WOC maps. Probably the middle is the toughest test of the detail vs legibility problem - http://www.woc2013.fi/ssl/woc.nsf/0/BF045E63A3EFE6B7C2257BA20042A0C0/$FILE/Middle%20Q%20MEN%201.gif First thing I noticed after reading the ISOM discussion on formlines is, there are a LOT of formlines! Maybe they should have used 2.5m. They have at least made the best of them by dash control, hardly any gaps in places of high curvature. Second is that the rock seems clear, even to the extent that they have been able to also use vegetation boundary dots! Malcolm Ingham's comment may tell us why: "Any rock features shown on the map are really big, meaning that a lot of rock detail of a size that would normally be mapped in New Zealand is not shown." And they have not resorted to representing the absent rock detail with stony ground dots as the JWOC middle mappers did. Other comments?

Show Profile  Michael Posted: 12 July 2013, 8:58 PM  
Malcolm asks an interesting question in his report on the NZOF website/FB page. The public race on the middle distance area had termite mounds marked, while the WOC race did not.


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