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Mapping

Show Profile  Bryan Posted: 16 June 2017, 8:44 AM  
Nice to have a 1m DEM over much of the country - from this we can then generate 2.5m, 5m, 10m contours in Ocad easily - we are certainly lucky to have this.

Some of this data is available right now - on Koordinates there is a 5M DEM for the Wellington region, and a 1M DEM (2011) for Wellington city.

There is also a 15M DEM for the whole country (derived from the LINZ 50K topo) and I've used this once or twice in remote areas to generate 5m contours but this produces very rough contours requiring a lot of work in the field to fix - better in steeper areas.

Show Profile  fraser Posted: 16 June 2017, 7:52 PM  
Bryan mentioned about the ability to import shape files in OCAD in another thread. This is also possible in the latest version of OOM. It sounds very promising with all this lidar data becoming available.

Show Profile  Michael Posted: 5 July 2017, 5:17 PM  
With the revision of the specification for standard mapping finally announced, the Mapping Committee has prepared three advices for various audiences. The brief statement that the IOF has declared that ISOM2017 is in; what this means for participants in New Zealand; and advice for NZ mappers. The first two of these have gone out through the ONZ website.

Amid exams and preparations for WOC, Nick Hann has managed the third of these, advice for mappers and a couple of useful resources. The rest of the mapping committee have finished them off and they will shortly be in the Mapping Resources on the ONZ website. In the meantime you can read a pre-release version at www.mapsport.co.nz/mapresources.html (the blue sections at the top).

Show Profile  fraser Posted: 6 July 2017, 10:07 AM  
Out of interest, how does OCAD handle the new boulder field and stony ground area symbols in respect to the area pattern clipping?

The unofficial release for OOM just cut the pattern off at the edge and as a result it can look quite bad, especially when two different densities are adjacent. e.g. http://imgur.com/a/yrhyY

Interested to know how it was implemented in OCAD.

Show Profile  fraser Posted: 6 July 2017, 1:13 PM  
Jim has sent me some samples, thanks. The clipping looks good in version 12, but cuts the same as OOM for versions less than that, which could cause problems for users on those versions (e.g. course planners).

Show Profile  Michael Posted: 6 July 2017, 2:03 PM  
We didn't previously HAVE an area symbol for boulder fields or non-yellow stony ground in the default OCAD symbol set, we placed triangles and dots ourselves.

OCAD's new area symbols in v12 are also supposed to implement the random dot spacing of the new spec, and I'm not that impressed. I think I'd prefer to keep hand-placing the dots and triangles, perhaps using a bit of the area symbol as a reference to what density to try for. I wonder if these differing densities are going to be recognisable by the runner.

Show Profile  fraser Posted: 9 July 2017, 8:54 AM  
I have found the area symbol for stony ground quite useful myself, but did notice the pattern clipping problem. I can't imagine the need for the boulder field area symbol for NZ terrain though.

If you are hand placing the symbols it should prevent any issues when opening the file in versions prior to OCAD 12 anyway.

Show Profile  fraser Posted: 12 July 2017, 9:52 AM  
At what height does a canopy become ignored and you just map what is at ground level? Any guidelines that people use?

In particular a building with an overhang with a high roof. It feels 50/50 whether it is too high up to notice and whether it helps or not.

This message was edited by fraser on 12 July 2017, 9:59 AM

Show Profile  Bryan Posted: 12 July 2017, 10:50 AM  
LINZ Data Service recently added 2013 1m DEM for all of Wellington Region (Includes Otaki, most of Wairarapa just short of Eketahuna, north of Castlepoint).

https://data.linz.govt.nz/layer/3621-wellington-lidar-1m-dem-2013/

Nice to be able to generate 2.5, 5m for anywhere in the lower part of the North Island.

Show Profile  Michael Posted: 12 July 2017, 1:39 PM  
Thanks Bryan, good news!

Fraser I've met differing views on this. Andrew Lumsden an Aussie who gave a workshop on sprint mapping recently says anything between you and the sky should be mapped. Others say the orienteer has a normal view at ground level, and that's what is important. I favour the latter, a canopy needs to "feel enclosed" and I wouldn't map an overhead walkway 3 storeys up. Are there many of those in Wanaka?-))

Show Profile  fraser Posted: 12 July 2017, 2:16 PM  
Thanks Michael, I like the opinion of a normal view and feeling enclosed. Not many in Wanaka, but give it a few more years!



Show Profile  Linley Posted: 12 July 2017, 8:04 PM  
General opinion from fellow mappers in PAPO is 'what the orienteer will notice' so your very high canopy will not be mapped by them.

Show Profile  Michael Posted: 13 July 2017, 4:08 PM  
Have enjoyed a play in the new sandpit aka the LINZ DEM for Wgtn. Contours (that OCAD can generate from the elevation grid) are highly plausible, but non-mappers please note - they don't just drop into a map. Normal measurement errors cause spurious wiggles and small hills, and (as they say) there are some places where it has measured treetops/roofs rather than the ground. It seems that laser beams have Monday mornings too.

We need to acknowledge Stewart Hyslop's valuable basemap role in the past, including seeking little glimpses of the gully floors in the photos, and smoothing unlikely bumps; but this will be great for new maps. And we'll be able to hugely improve some which, for various reasons, were based on the archaic topo contours.

Thanks LINZ, and the enlightened govt policy which makes this data freely available. (Gossip from Oz suggests many obstacles there.) Thanks for the news Bryan. Other areas covered so far include Auckland, Tauranga and lots of bits of Canterbury.

Show Profile  The Map Guy Posted: 13 July 2017, 10:38 PM  
Yep. Role on the rest of the country having LIDAR data freely available. The 15m LINZ DEM data has limited use, especially in flattish areas.

I agree with Michael's comment about Stewart Hyslop's expertise.

Show Profile  The Map Guy Posted: 13 July 2017, 10:39 PM  
Think it should be "roll on........."

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