Orienteering NZ Wiki

Imagery, Photogrammetry, LIDAR, Buildings, Kerbs etc. This is WHERE to get data, there may be other topics which discuss using the data. This page covers discussion up to 2010, for later discussion see Data Sources from 2011

Related categories: DEMs, Google Earth, OCAD - Getting Data In

Is laser scanning and orthophotos about to replace photogrammetry?

I see the Danish Orienteering Federation has just made a deal with the supliers of laser contours to supply their member clubs with laser scanned contours and orthophotos for mapping purposes.

Cost to clubs were shown and I have converted them to NZ $ using the latest exchange rates: NZ $ 210 for 0-4 km2 + $ 105 for each additional 4 km2

Where are we at here in NZ regarding laser scanning? I see it is available here. NZAM are certainly advertising it on their web site but their prices frightens me.

Should the NZOF be taking a leading role in making this new technology available to clubs?

it's already available in the auckland region and being used. check out the auckland sprint champs map on RouteGadget for an example. Selwyn made that map from LIDAR.

Jim Lewis and I have verified that we can get selected layers of topo map into OCAD. The process involves selecting and downloading from NZTopoOnline (LINZ website), in a format called “shape files”. Jim has OCAD Professional which can import shape files. This is relevant mainly for rogaine and MTBO mapping.

Chris Forne can also handle shape files and he may like to comment here.

I have imported LINZ Topo Layers into OCAD by importing DXF files.

Note that the DXF files are not readily available - the company I work for (Terralink) has converted all the data into DXF (as at 2005) and I have access to it. Terralink obviously provides it for a cost but as long as it's only a small area, anyone wanting say one 1:50000 sheet could twist my arm.

To add to Bryan's post, DXF files import into the standard version of OCAD. Bryan's offer is therefore a most useful one.

I too have used DXF to make 1300sq.km of map around Wellington, but I felt I was over-twisting the arm of the person who was converting into DXF for me. That's why I looked into the shapefile method. Of course Jim is entitled to make a charge for his investment in OCAD Pro and his time.

Hi, You can download all the topo data from LINZ topo online in Shape file format, however at present I have only figured out how to do this one screen at a time. Therefore, for a large area, I have to repeat the process, making sure I have the right offset so the various map segments fit together nicely afterwards.

When exporting the data I select the box for every single topo symbol, so that they can all be converted into OCAD. I have written a little program to do the conversion for me, as well as join all the map segments together properly. This also allows additional information to be extracted such as the contour heights to create index contours, or relief shading, correctly convert different road/track types to appropriate OCAD symbols, plus many other useful features. It works fine on standard OCAD version.

At present I am doing this for a small fee, so if you are keen to make a new map let me know. I am also planning on writing some more software for fixing OCAD issues, such as duplicate symbols sets, or converting old maps to correct IOF symbols.

After lots of mapping based on LINZ topo data I've found it pretty well as per the printed topos. I recently found a missing hilltop though. It would hardly be surprising if a few small features had been missed in the digitising, so be alert when using them.

The one-contour hill is centred at NZMG 2671080 5988380 or just north of control 71 in the Eastbourne Rogaine. It nearly caused the control to be put in the wrong saddle:-))

So Shaun, you traced your whole map rather than just getting roads exported in a format that you could import into ocad and change symbol on - like I believe Taranaki did for its New Plymouth street maps

Yip - have you tried to get information from councils? It was late enough in the piece that we got what we did.

Good to knwo other sources for this information though for next time I have to map a city!

The LINZ website says “Orthophotos are no longer commissioned by LINZ so no further images will be added to this collection.” So we'll have to pay aerial photo companies where we want later coverage or areas that LINZ never got round to. Those who have done this might list here the companies and indicative costs.

I've not used orthophotos very much - they usually were too expensive to pay for (because the aerial photos have been rectified and are registered to a map grid).

I have access to New Zealand Map Grid images over the whole country via my company, Terralink.

Other sources are: local councils, New Zealand Aerial Mapping, Google Earth, Microsoft Virtual Earth.

Quite often these days I don't order photogrammetry - I just interpolate contours from the LINZ 20m contours, overlay aerial photos in OCAD - just use the normal registration method in OCAD - this is fine for Orienteering areas which are only a few square kms. Recently I created a 5m base map and had a choice of Terralink images and Google images. I choose the Google images as Google drapes a 20m 3D terrain model over them and when interpolating you can pick out the gullies and ridges better.

All local authorities in NZ has access (licence) to high resolution photos from the Quick Bird Satellite. The latest photos I got were only six months old. Because our club is an non-profit organisation there was no cost involved.

IMO Google is not a replacement for orthophotos. They seem to be stitched together in a quick and dirty way, and there's definitely height distortion.

You are lucky Svend. The 5 councils in Auckland Region have varying policies re sale or supply of Photo data. Outside of Auckland city it seems the local body can supply small “tiles” (about 2 or 3 standard suburban street blocks)free if they wish, and some do. Bigger areas for the whole region must be purchased through Auckland City Council who hold the licensne and selling rights for the region. They have given a 50% discount. I have found google photos to have distortion in some areas and the tree shadows are usually enormous compared to good summer orthophoto.

In regards to the use of images: In my opinion, Google can be used in some instances instead of orthophotos and aerial photos. In the case I mentioned, I also had access to 'high' resolution images from my work but there really was no comparison. Instead of one to two images from my work, I stitched together 15-20 images from Google in Ocad - this removed the distortions as I worked on small pieces. In Google I could see all fence lines, all trees, some sheep and lots of detail but for my work images I could not. What I've found is that this will not always be the case and I'm lucky to be able to have access to different sources and compare before I choose.

we had a lecture on Lidar recently, from an American guy who was using it extensively. The latest technology is using photons.

I'll see if I can track down the slides, here is the abstract:

LIDAR or Laser Detection and Ranging is a rapidly maturing technology that provides rapid and highly detailed characterization of natural and constructed surfaces. The elements of LIDAR include a laser and receiver. The laser emits high frequency pulses of coherent light and the receiver times, counts and processes the reflected pulses of light. LIDAR is analogous to RADAR except is sends out narrow pulses of light versus broad radio waves. The laser return power (intensity) is indicative of the reflectance of the surface and the timing provides a measure of distance from the laser. When LIDAR is coupled with a global positioning systems (GPS) and an inertial navigation system in an aircraft, rapid, highly accurate characterization of both the earth surface and above ground structures or vegetation is possible.

There are aerial photos and there are aerial photos. Some are taken high in the sky and Stewart Hyslop can't see the detail in his stereoplotter. Others are low down and Stewart can pick up a sheep. Some are digitised and corrected to agree with a certain map projection, others are not. We all know this and ask certain questions when photos are discussed.

I wonder if there is LIDAR and LIDAR? I think that an aeroplane goes up and collects data. Then that data goes into some software which turns millions of data points into various things including contours. That software might be told to interpret treetops (for a forest company) or the ground (or the water table under the ground) might it not? It might be told to produce accurate contours or smoothed contours? It might be told to look for vertical surfaces (if you are a local body looking for unauthorised buildings)? Etc etc.

I think we might need to learn what questions to ask about LIDAR output.

They spend about 6 months filtering and interpreting the LIDAR data, simplifying it into the output that's available to us. I gather it's quite a manual process.

If you've been supplied with geo-referenced JPG files and you want to tile them together only OCAD10 will allow you to do so (no problems with geo-referenced TIFF files with OCAD8 and9). The really neat thing that I've discovered is if JPG files are imported into OCAD10, then saved as an OCAD 9 file, the images will then import geo-referenced into OCAD9.

So if you haven't upgraded to OCAD10 and have to work with JPEG files give them to somebody who has OCAD10 and they can do the conversion for you.

Note there are two files for each image - the graphic, and a world file (has co-ordinates for that image). For TIFF files the set have suffixes: tiff and tfw For JPG files the set have suffixes: jpg and jgw

Note the “set” must have the SAME prefix.

Of course you can always do it the hard way: save the JPG as a TIFF, then change the corresponding TFW suffix to JGW. TIFF files are very large.

I recommend using geo-referenced images if you can get hold of them. Great for Park maps - your Council will have the images. You don't have to adjust the background map/template.

In November I wrote… “I have also changed the offset values - from their NZMG values to the NZTM values. I was prepared for complications…”

I have learnt that you can't change a map referenced to NZMG, to NZTM, quite so easily. The details are gory, let me know if you want to discuss. I just want to correct this wrong statement.

If you're starting a new map or georeferencing an existing one, I think the time has come to use NZTM. This new grid system has nearly reached “consumer level” with a whole new set of paper topo maps due for release in September 09.

I believe the changeover date is 23 September 2009. Many cartographers have been drawing maps in NZTM for several years now.

You are right about the georeferencing bit Michael - especially if the map has been derived from Shape files which have their own database. Start as you mean to continue is the maxim!

However all is not lost as it is possible to put a NZTM grid onto a map which has been drawn in NZMG/Geodetic 49 format. Reasonably satisfactory for 1:50000 and 1:25000 scales for “small” areas - say around 100+ square km

Thought some of you might find this interesting:

http://okansas.blogspot.com/2009/06/lidar-contour-comparison.html

A great source of info Tane. In particular the Orienteering/North America article is a very readable summary.

I suspect however that the picture of US topo contours overlaid on some LIDAR-derived contours presented by Kommentator O'Kansas contains a fallacy. That is that the more detailed set of contours is correct. Many of the wiggles in LIDAR contours may be spurious. Occasionally Stewart Hyslop's photogrammetry shows wiggles that you can't see on the ground, but having a human involved is effectively a “reasonableness filter” which might not be there for LIDAR contours.

Tane, Thanks for putting up that link. After the OCAD session here on Tuesday I got a hankering to find out more about LiDAR and it's pros and cons. Michael's comment about spurious wiggles will probably be backed up by more research and fielwork.

LiDAR seems to have quite a few applications particularly in Robotics and for Military applications such as UAV's so I guess the technology will develop and improve rapidly…but hopefully not to the extent that the machines take over…otherwise it will be down to John Connor to save humanity!

As NZ adopts a new coordinate system for its topo maps (NZTM) this page from the LINZ website might be handy: http://www.linz.govt.nz/topography/publications-faqs/index.aspx

Here's a website dedicated to the new coordinate system for NZ topo maps. I think it's more useful than the one above, with a good range of further links.

www.topo50.govt.nz

Sing out if you want to discuss the application to orienteering mapping.

The LINZ orthophotos are a free source of distortion-free location information. For many areas however you have to use photos related to the old topo map series and grid. That's no big deal because you can convert their corners to the new grid and hence place them sufficiently well for our purposes.

That is, if you know where the corners of the old topo maps are. LINZ used to have this on their website, but the baby has gone out with the bathwater. I have obtained the info from them, pending reinstatement on LINZ I have put it on www.mapsport.co.nz/260mapcoords.html

Yes it's more logical to have Eastings first, then Northings.

This is interesting: http://www.attackpoint.org/discussionthread.jsp/message_369620

A decision you would need to make is whether to put your effort into improving the open-source map of your area (adding all the missing tracks etc) or whether to develop a map of your urban area in OCAD as we have for greater Wellington.

Here is a direct link to the opensource orienteering page showing christchurch. No contours on here yet. They have now added the ability to create a score event map. Very new, course setting hangss every time on my machine at the moment in Internet Explorer but works perfectly in Chrome. As Michael mentions, generating a base map from this data, updating open source then putting your course on via this tool may be the way to go for future street events. Especially in Christchurch when we are not on the hills.

http://oobrien.com/oom/?zoom=15&lat=-43.5306&lon=172.6206&layers=B00FTFFFFF

I'm not too keen to make our mapping open-source at present, having just had the regional council advise there will be fees to use its land for the rogaine champs:-((

Woops I lashed out blindly there, this really pipsed me off after all we have contributed to the regional council.

My more considered response is that open-source mapping will be good when we need a map at short notice eg when a community group wants something in a particular place. And the place is flat.

But I think that we should all have our entire urban areas in OCAD at a level of detail between the normal o-map and a topo map. This same mapping can be used for street events, after-work rogaines, MTBO, city safaris; and as a framework for normal and sprint maps of small areas. Its not that hard to set up and you don't do it all at once like normal mapping, you fill it in as required. I've got a network of nosey runners and riders, many outside the club, who give me updates as they find stuff.

The main advantage of having it in OCAD is contours. Even if contours become open-source, they are likely to be the 20m topos. We've made a fair few changes to those over the year (eg hilltops and reentrants that fall between the 20's) but more importantly we're now wheeling in 10's obtained from local bodies. These are hugely better.

Another reason, and its subjective really, is that this mapping has mostly low detail, but there are interesting places where we want to cram in as much as the scale (1:20 or 25,000) will permit. I think we need control of the map production to make the most of this; and probably many other cartographic issues

In summary, if we recognise that close-to-home is important for orienteering participation, I think we'll want to have control over the mapping. 65-70% of participations in Victoria come from park/street events (AO March 2010 p10)

This discussion on Attackpoint seems to confirm what I thought - that there are various types and qualities of LIDAR results. http://www.attackpoint.org/discussionthread.jsp/message_406673

If you need an introduction to LIDAR try this link from the discussion: http://www.catchingfeatures.com/eddie/other/lidar_basemaps.pdf

I spent $30 on some of the new topo maps today. You know, the great new ones that were introduced with a fanfare last year. I haven't stopped laughing, great investment on a gray wet Friday. Now its getting a bit chilly, think I'll light the fire…

“TopoOnline will no longer be available from 30 June 2010. LINZ has made each of the Topo50 map sheets available as image files (TIFF and GeoTIFF formats) and data files (Shape and IFF formats). These files are available for free download using the choose a map tool at www.linz.govt.nz/map-chooser.”

So no more screen grabs, you download data for each topo map.

Could be sizeable. Probably not going to be ideal for the selective areas we are interested in. We will end up making a big map and then taking partial maps off it.

The shape files can be converted to dxf files for use in OCAD 8 and 9 by using a free download FGIS.

I won't shed a tear, I was never on the same wavelength with it, one blink and you'd be back looking at all of NZ.

But it IS strange that the alternative tool is based on the artificial concept of “sheets”. NZ's best areas are all between the sheets. I'll rephrase that, on the border of two sheets if not at the junction of four. With the old maps there was a junction on a MTBO/rogaine area at Te Marua, Upper Hutt. With the new sheets there's a junction above Greenacres, Tawa which is crying out for a map. Which would of course be named after the trig, “BONK”.

Thanks for the info on NZTopoOnLine Richard.

Getting rid on NZTopoOnLine is a BIG step forward. Unlike Michael, I have successfully used it many times, but it has been a pain when you are limited to small areas for downloading, and have to do multiple downloads. I used to keep forgetting to select key features (e.g. native bush).

With the new system you get EVERYTHING on the sheet (around 3.5MB zipped Shape files). Beats the 140MB of the Tiff files.

Sod's Law seems to always apply to the area you want: always along the seam of multiple sheets.

But it is no big deal if the area you want covers 2, 3 or 4 sheets. Just download what you need, and convert into OCAD. Everything should butt together as do the printed NZTopo50 maps.

OCAD10 Pro handles BIG maps. You can always crop out the section required and then import them onto your main map if you are using OCAD8Pro or OCAD9Pro.

This is long overdue!!!!!!! Good move LINZ

Have aerial surveys been performed here in NZ for mapping? I presume they would give substantially better info for mapping. Possibly not so good in forested areas but perhaps still useful for open areas and clearings. It also seems like they can do contours based on the photos. http://diydrones.com/profiles/blogs/smartplanes-unmanned-survey http://www.smartplanes.se/

No answers to my question above? Ok, I'll muddle my way through as best I can.

On another topic, here's a film showing how it all was done - thank our lucky stars we don't have to scribe or draw with pen and ink anymore. I have to confess (showing my age), I have done most of the things shown in the film at various times.

The film was made in 1971 about map making: http://www.ecasttv.co.nz/program_detail.php?program_id=1662&channel_id=60&group_id=68

yes Bryan, i remember you wearing tight flared slacks and slim fitting plain coloured shirts with big dracular collars. Isn't it amazing how fast things change, incl speech. At first the advent of the digital age seemed terrible, seemingly removing the fine control and artistry skill in mapmaking, graphic art and typographic world. Most of what you learnt became obsolete soon after that. Patients was a virtue back in the day, it just looks like impossibly frustrating hard work now. Nice find.

Pity that our central government mapping agency has given up on the updating process - the topo contours are the same as you saw being made and at least around here the accuracy of manmade features is awful. I think they stopped when their last Trekka stopped running.

LIDAR has taken over for contours but it's commissioned piecemeal by local government and there's no central source of NZ elevation data. And local government doesn't seem to be in the business of general-purpose topographical mapping, I think they are primarily concerned with managing their assets.

If we all got together (central and local government, private enterprise street and roadmap producers, orienteers) with some sort of wikimap, we should be able to eliminate duplication and produce something really good. Am I dreaming?

Michael, it exists and is called http://www.openstreetmap.org/. What's more Micro$oft recently decided to back this in an attack towards Goooooooogle: http://www.idg.se/2.1085/1.355711/microsoft-attackerar-google-maps--sponsrar-oppet-initiativ

When we talked about this in March there wasn't any contour or height info. Is there now? What is Microsoft's aim Al, my Swedish isn't up to the second reference.

Ooops - sorry Michael, I cut and paste too quickly. It was a link I saw recently…. Anyway - the Google translation is okay I think: http://translate.google.com.au/translate?hl=en&sl=sv&tl=en&u=http://www.idg.se/2.1085/1.355711/microsoft-attackerar-google-maps--sponsrar-oppet-initiativ

Micro$oft's aim? World domination or something like that I thought ;-P Actually - I think they realised that they can't compete against Google on their own…

There's a “Walking Access Mapping System” at www.wams.org.nz which might be useful for identifying orienteering areas, or access to them. It shows reserves, most categories of crown land, and roads both formed and unformed. This is overlaid on either the topo map or an aerial photo, and the match is much better than Google's.

This has been produced by the “Walking Access Commission”. Its objectives seem quite broad, including those of hunting and fishing. The commission is led by John Acland, I think he's a former Meat Board Chair, at any rate the Acland name is prominent in farming circles. See http://www.walkingaccess.govt.nz/about

At least around cities the access shown misses a lot of what appears to be public, perhaps because some council land is under ordinary ownership, or tracks are de facto rather than legal. On the other hand, it would not pay to be too assertive about “paper roads”, which are often in a different place from any tracks on the ground.

It isn't clear how up-to-date the data is, but the system provides an easy way of asking questions about specific places. It's “under test” until the end of Feb.

My company Terralink won the tender to provide the platform for the WAMS system. It shows only legal crown access and is maintained monthly from the current LINZ cadastral system. It also shows Terralink aerial photography which in some cases will be higher resolution than Google.

I agree in some areas it leaves a lot to be desired from the 'actual' public access in reality. I'm sure it will cause debate and one of the WAC's functions is to make public access more well known. Your feedback will provide ways to improve the website.

If anyone wants to know the legal ownership of an area and its not clear on the WAMS system you could contact me and I could research it fairly easily (as part of my job) from the information I have access to.