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Mapping

Show Profile  NSmith Posted: 1 September 2016, 3:22 PM  
http://news.worldofo.com/2016/09/01/were-the-woc-2016-maps-good-enough/

The modified maps look much better without all the extra formlines. I also thought the vegetation mapping was way over the top considering what is readable at high speed.

Show Profile  Michael Posted: 1 September 2016, 4:31 PM  
Thanks Nick, I hadn't see WorldofO's examples when I wrote the above. Though it has to be said that taking off some details ALWAYS makes a map look cleaner, the question is, when I come across that distinctive little feature, where is it on the map? And that's a question of the prevailing scale/style. Which has been debated for 100 years, heh heh.

Hi Map Guy, in common with some other large events, the way to find some of the details including results and maps, is to go to "live". Even though the event is well and truly over. The website is www.woc2016.se.

Oh and another thing I noticed on the relay map was what appeared to be marshes with regular holes in them. (I hope its not my laptop screen that has holes in it:-)) I surmise that might be intermittent marsh. The "indistinct marsh" symbol would probably have sent the same message but maybe like me they don't like that messy symbol. Thoughts?

Show Profile  Mike B Posted: 1 September 2016, 10:35 PM  
Has anyone seen the WMOC maps from Estonia. I have a couple Selwyn gave to me on his return. The long was drawn with 5 metre contours but just about every intermediate contour was also drawn as a form line whether it was necessary or not. Seemed way over the top. They may as well have made the contour interval 2.5 m and be done with it.

Show Profile  AlisterM Posted: 2 September 2016, 10:07 PM  
The World Rogaine Champs map also had a surplus of formlines, many of which provided no extra information, but distorted the normal impression of steepness from the contour spacing.
The map can be viewed here http://worldrogainingchamps.com.au/index.php/event/news/84-news/218-wrc2016-event-map

Pre-event information described the mapping as "The map was prepared specifically for the WRC using the latest digital aerial mapping technology. However, apart from the immediate vicinity of Checkpoints the map has not been field checked. It is NOT an orienteering map!"

It seems that technology is providing detail that mappers and cartographers are loath to remove, even if it is at the expense of clarity at the printed scale.

Show Profile  Michael Posted: 2 September 2016, 10:42 PM  
In both cases a human mapper decided which bits of the intermediate contours to put in. The rogaine map is certainly OTT.

Show Profile  Doug Posted: 3 September 2016, 10:53 AM  
Hello orienteers!

Michael, in response to your post "Topo Map Extents - relating a map sheet to coordinates" (8 July 2016), LINZ has a few coordinate conversion tools you can use here http://www.linz.govt.nz/land/maps/topographic-maps/topo50-maps/converting-topo50-coordinates

These tools allow you to enter in any coordinate and they will return the NZ Topo50 or NZMS 260 map references. The first part of these map references gives you the mapsheet number the coordinate is located in. I like the "New Zealand Map Reference Converter" tool which you can use offline. You can also carry out any other coordinate conversions and can change WGS84 degrees minutes seconds to decimal degrees in the options.


Show Profile  The Map Guy Posted: 4 September 2016, 12:59 PM  
I agree with Alister's and Michael's comments regarding the excess number of formlines in the World Rogaine Champs map. The vast majority of them are unnecessary - especially when a 10m contour interval was used.

How experienced were the fieldworkers? From the comments above most of the map wasn't fieldworked (apart from around the control sites) so the decision to add those formlines were from an armchair cartographer????

The extra formlines detract from the clarity and ease of reading the map, and interpreting it against the terrain - the very opposite of what they are supposed to do.

Mind you it is easy to say the above from just looking at the map on a screen. I wasn't at the event and I have no idea if those extra formlines actually aided or hindered the competitors. I'd be interested to hear what the participant's thoughts are.


Show Profile  Michael Posted: 4 September 2016, 5:59 PM  
Yes the bottom line is whether competitors feel they help. But there's also a test we can make from our couches. A formline that's halfway between the adjacent contours provides no extra information.

Show Profile  mcroxford Posted: 12 September 2016, 12:04 PM  
Has anyone accessed the New Zealand Petroleum & Minerals aeromagnetic survey datasets in order to determine whether they provide a low-resolution ground contour data set yet?

http://www.nzpam.govt.nz/cms/tools-and-services/geoscience-exploration-data

Data is now available for large areas of Marlborough, Nelson, West Coast, Southland, Otago and the Waitaki River Area. I am trying to determine whether the data can be used to create a base contour map especially for areas with native forest cover.

Show Profile  Rog Posted: 27 September 2016, 2:24 PM  
Is this online drone mapping service of any use?

https://www.mapsmadeeasy.com/drone_mapping

Show Profile  mcroxford Posted: 27 September 2016, 3:10 PM  
I found this site interesting regarding instrumentation carried on drones.

https://www.dronezon.com/learn-about-drones-quadcopters/best-lidar-sensors-for-drones-great-uses-for-lidar-sensors/


Show Profile  Chris Forne Posted: 10 October 2016, 3:51 PM  
Hi Guys,

I have just purchased a DJI Phantom 4 drone for mapping.
I flew a survey around Castle Hill village using free Map Pilot App by mapsmadeeasy last week and processed the images using Pix4D trial software.

Seems pretty awesome in open areas - I can easily get accurate 0.5m contours or even finer if you want. As it uses structure from motion photogrammetry approach for producing the 3D models it effectively gives the canopy height rather than ground height, so not so useful in heavily forested areas.

One of the cool advantages of photogrammetry approach is that you can generate high resolution orthophotos which align with the contours.

Definitely the way to go for producing great base data for open/semi open areas and urban terrain, so if anyone is planning on doing some mapping in such areas, feel free to get in touch.

Show Profile  nh Posted: 20 November 2016, 7:46 AM  
Earlier Michael mentioned that the information contained here and in the Printing thread would be transferred to a new site where the information could be sorted more easily to allow better access. This has now been completed by Michael Wood and is available to view and edit at: http://wiki.orienteering.org.nz/doku.php?id=mapping:mapping

There are 23 separate headings, such as “Printing” or “Digital Elevation Models”, under which the relevant posts from Maptalk have been categorised. Some headings have subtopics, for when there were too many posts for a single page. This should make it easier to find information on issues that mappers face, so now, if you are struggling or unsure about something, check the Wiki as it may have been discussed already.

While mappers are free to continue to use Maptalk, the committee urges mappers to register for this Orienteering Wiki (it's not just restricted to Mapping) and to contribute here for the good of the sport. Registration is only required for contributing; anyone may view. There are instructions on the page for how to contribute. Thank you for your contributions!

Show Profile  davenev Posted: 13 December 2016, 9:17 AM  
Hi all,
I will update a ridge this summer, it's steep - you can't run up the sides, semi-open, with rocks from 0.5m to 5.0m and a few small cliffs.
ISOM says, over 1m. Would we measure that from the downhill side, the uphill side, or take an average, or just pick those that say, Pick me ? Which is pretty much what I did 4 years ago...
Dave Nevin, Whangarei

Show Profile  Michael Posted: 13 December 2016, 12:22 PM  
I've made a comment on the mapping wiki under "Generalisation and Simplification".


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