Orienteering NZ Wiki

Comparisons between different mappers on the same area, onsite reviews, offsite workshops

Related categories: Generalisation, The Scale Question, Interpreting the Spec

Last year I suggested a meeting as below. There wasn't any interest then. I always learn something when I visit Jim Lewis and he has agreed to host a mappy-chat at his place on the Sunday evening of Waitangi weekend. No doubt the role of Google Earth in the process will be included. Let me know if you want to join us.

Last year's posting: I've been grappling with using NZ Map Grid coordinates and LINZ orthophotos as a way of providing a framework for map extensions or joining maps together. And removing distortions caused by less than perfect joins in the past, which have led to fudges at overlaps or underlaps. If there's anyone else who has done this I wouldn't mind a chat at the Wgtn Champs at Labour Weekend - one of the evenings - at Wanganui somewhere. RSVP to michael.wood (at) mapsport.co.nz.

I don't really agree with Paul that remaps are suitable for apprentices. I,ve worked on quite few remaps and it takes experience to make judgement that relativity may not be right in some areas. Indeed sometimes you need to go back to the original photogrammetry (never disgard it, even hough you may have the map on OCAD)to discern which are the correctly mapped features.We are working on a 1981 Steve Key map (Steve was Aust. leading mapper and went onto map the USA World champs) and while he made a good map in some areas from what was poor photogrammetry(Swedish firm)he fell into the trap of believing the base map 100%in one instance and placed 2 hills on the end of a flatish 125m spur given on the photogrammetry.As there was not much else to work from in a flatish area mapping continued as though they were the correct relative feature to work from. In actual fact they were 47 m further up the spur from were the photogrametry ran slightly down hill and this was not discovered until features did not matchup from another direction. The area had to be fieldworked again with the hills correctly placed and the end of the spur shaped by a form line. I doubt if an apprentice would have pick up on this. Give me a virgin (map)anyday to work on.

Hi ole codger ! The problem I suppose with this forum is that every little thing you say can get picked apart. I suppose it is quite entertaining anyhow. I wasn't really discussing apprentice mappers at any detail, it was originally in general discussion saying that I personally, like yourself would prefer to deal with a virgin map than fix someone elses screwups ! (not that I might not make any myself). I agree with you that remaps can be hardwork too, a really poor map would indeed require someone with experience to sort it out. But I don't believe either that it would be a good idea to send anyone without a proven vast mapping experience to attempt a map like White Lightening, as much of the photogrammetry was very difficult to use and did not show a lot of detail. Anyhow it's good to have another mapper speak out because if we don't swap opinions or ideas nothing ever changes and we get stuck in ruts. Where are the rest of us? Today I went out doing some control site checking, I was with the course setter and we came across a few areas requiring map corrections. It was very helpfull to have someone else there to discuss the situation with and see their point of view,. It made me think that all mappers really should do some map walks together more often, along with apprentice and interested mappers. I'm looking foward to your remap of Waiuku and had been wondering how the mapping styles of way back then compare with today, and whether the 1:10000 scale will be more suitable.

Can I rephrase what I wrote above? I welcome creative EXPERIMENTATION, not rule-breaking. We have B-level events and below where things may not be strictly to the rules. A-level events should comply with the rules I reckon. Which isn't to say the rules should never change, but only after due process.

The mapwalk idea is good Paul, we've been saying for years we must hold some advanced mapping get-togethers. There's nothing I can say on a forum like this about how I cope with remapping in detailed sand-dune terrain. Except to say that taking off the knolls and depressions that are under 1m deep/high is a good start:-)) And I reckon that if I'm in some doubt about whether a feature should make it onto the map, then “off” is usually the best answer.

Ole Codger, ditto to your comments about questioning position. In spite of the attraction of virgin areas, the big need facing us is fixing existing maps. It was like this in software development too - everyone wanted to write new software, the big need is in maintenance.

We ought to compile a list of those who do enough mapping in NZ and through correspondence set up a mapwalk or two. I know you've tried before Michael, but we should keep trying. Those who attend will be the beneficiaries. Sand dune terrain should be our focus. We are using three sand dune maps over the nationals extended w-end, Waiuku, Stags Roar, White Lightening, so maybe this is our opportunity while most people will be attending these events. I know it may be a bit of a pain in the preverbial, ie; I have my family to fend off, so these walk/discussions don't need to be too long. One concern that arrises is that we probably all do not want our mapping work scrutinised by our peers for all to see, so are a little reluctant, we need to remember that we are all human, we all make mistakes, we all have good and bad days and MOST IMPORTANTLY no one way of mapping is ever the only right way. Experiments have shown that most people see terrain slightly diffirent from each other. Our aim should be to be more consistant. A nuetral map could alleviate awkwardness but is probably harder to get organised. The last thing that needs to happen is that it turns into a heated debate as we defend our differing views! We could try to walk aimlessly through the map commenting on observations, visit problem areas that we thought were either over or under mapped, and anything else that we can think of. I don't think at this stage it needs to be as formal as a mapping clinic. Anyone interested?

Yes me. I'll be around during the week after Easter altho locals will probably be working. An off-map meeting (evening) may also be useful, as I said I always learn things when I visit Jim Lewis. The recent meeting I set up at Waitangi Weekend had two participants - Jim and me:-))

Mapping SHOULD be scrutinised for all to see. Areas of interest are those which gave competitors trouble (to find out why). And areas which gave the mapper trouble (if they turned out fine, that's also valuable to learn from). It may not be easy to find such spots in close proximity, as the majority of most maps may not fall into either category.

I can think of many areas on white Lightening that as a mapper presented difficulties, and also areas I had trouble on as a runner. I'll be there on the WEnd following Nationals, but not mid week. I'll be working during the week, in the evenings/nights, so unfortunately can't meet up then (unless its really raining cats and dogs). It would also probably be more beneficial to look at more than one map.

Who are the mappers we need to get on board? I think we all have a responsibility, as a group of paid contractors working for orienteering organisations, make an effort here to meet very occasionally to discuss matters. As I have said, I'm not really aware of all of the mappers these days, obviously us two, Jim, the Aspins, Mike B, Teahans, Robbie … there must be heaps more. Can we set a couple of dates and contact everyone.

My preferences are: after Waiuku Middle distance - Sat 7 April, after White Lightening - Sat 14 April, after Stags Roar/Spaghetti Soup - Sun 15 April. (although I probably have to pick up controls for this one).

These are just my ideas, maybe there are other possibilities to suit others?

Paul and Michael and etc, I've enjoyed reading your mapping comments. White Lightning was one of the poorest maps I have encountered for legibility. The gap between brown features was much too small and the appearance was very fudged. I examined the map at home under bright light using a 8x magnifier and still struggled to read knoll features. Orienteering in the field was a bit of guesswork even using a new pair of O glasses from the MapShop. (guesswork can't be too bad as I had one my better runs for a long time!) One of the problems we face with legibility relates to using laser printers. The older maps Paul refers to (“maps were a work of art”) were printed very precisely and clearly using off-set process. I remember changing pens to 0.13 where the brown features became close together, and also holding the drawing pen very gently to get a finer line. The orienteers had no problems reading the map. Try getting a strong (8 times) magnifying glass onto a old off-set map and comparing it to a new laser printed map. The laser map is just a series of nebulous dots. My experience so far with city park maps and especially maps drawn to IOF Sprint standards is that they take many times longer to draw than a forest map. Very much appreciated Svens refrence last year to kell@soenniksen.dk: it made my approch to sprint maps somewhat more rational. Is anyone else interested in the Aussie mapping workshop in June? Grahan Teahan says he is. I would be happy to join others on a mapping discussion venture, in the field or in the armchair. I'm away during the weekend after Easter (Ruapehu offers more interest) but I'm free during the week.

Hi Selwyn ! Watch out for stray lahars. Finally someone else has identified with precisely with my W/L knoll legibility issue. I was beginning to think I was all alone with my imaginary thoughts. Without being too repetitive I also think the specification sizes of some of the other features adds to the problem. To me the Wounded Knee map using the old specs is far far easier to read! Those b—dy fuzzy lines. They seem to more fuzzy than most, maybe some printers are better than others. I am very interested in the Aussie workshop, especially if we head down the GPS direction in the future. But I'll probably have to give it a miss. I can't think why but the rest of my family would rather go to Fiji and I can't afford both. It would be awesome if you guys go and upon returning produce a detailed report for those who can't.

It appears that a number of mappers are available during the week of the Aftermatch Carnival. Michael, Selwyn, Tricia and Wayne seem keen on meeting at White Lightening Mid week on the thursday. I should also be able to rearrange work commitments around this if this is our only option. As I have said it will not be difficult to find areas of interest on this map as the photogrammetry was differcult to use, some area's were very vague with subtle cotour changes and others quite complex. It may be of benefit to see some of the base material we had to use. We were also on a very tight schedule and had to rush things a bit, so I'm sure there will be some areas that we will find that could be easily mapped and represented in a different manner. After discussion maybe it would help to pick a tiny area of this and do a fieldworking exercise to see the way others would map them. There are other area's that I am happy with the results where I had to generalise a fair bit, that would probably be worth looking at, and a couple of spots were I initially generalised a little too much , then remapped after the course setter pointed them out. The result being more accurate but also possibly a little complex on the final map. I still believe that it would add benefit to visit other maps in slightly different terrain produced by different mappers if possible. If everyone is still keen we could pencil in the date and someone could volunteer to contact others who may not have read the Maptalk forum.

Thanks Paul. How about we aim to meeet at about 1.45 pm at the White Lightning event and meet for a mapping discussion on a piece of terrain that Paul thinks is suitable. Obviously would be useful to know numbers. Paul, if you want some workshop sheets printed, you could email or post something to me before the day.

OK that sounds sweet as.

Would all of you guys and gals interested in the mapwalk/discussion at White Lightening, 1:45pm Thurs 12 April please let me know if you can join us. Email me: paul.irene@xtra.co.nz Include anyone else you have spoken to who wants to come also. Has anyone contacted Jim Lewis or Mike Beveridge?

I'll put my hand up to gather topic info and come up with a stratigic plan to cover as many topics as we can on the day and visit appropriate sites on the map.

So I need each of you to email me your list of subjects or issues you wish to look at or discuss, and what your goal is from attending this informal mapping (fieldworking) workshop. From your requests I'll try to put together some brief paperwork notes, and map material that we can use so that we have a little structure and so we can make notes as we learn from each other on our quest for more consistant mapping!

Some ideas I can think of… 1. Generalisation: when to, and examples of good/poor generalisation. 2. Vague sand dune terrain: How to/not to map, problem solving. 3. Complex area's: over/under mapped. 4. Poor base map or photogrammetry: swapping ideas for surveying these difficult situations. 5. Different mapping styles: not neccessarily right or wrong, but being on the same page. 6. Vegetation: Greens. 7. Veg boundaries and clearings: what, when and how, in the interests of map clarity. 8. Formlines: not enough/too many. 9. Those b—-y depressions and knolls. 10. ISOM 2000 Specs. and digital printing issues and how to convert our previous specification maps. What are our options if the terrain is very complex. 11. What the orienteering public want/dislike on a map. 12. Future mappers: are they born? can we help? Do we have a problem. 13. ??? Maybe bring other maps to discuss problems that arose with them…. Bla bla bla whatever.

Anyway I could probably go on and on, but I want your problems or issues that you would like to try to address so that this workshop is worthwhile and so we all get something out of it, apart from mingling in the woods with fellow enthusiasts and a cold beer afterwards!

Coming along so far then… Me, Carsten, Selwyn, Michael? Tricia and Wayne? We need more.

Looking forward to hearing from you all. Anyone happy to be MC on the day, please feel free!

May you run like the wind at the nationals, unless you are in my grade. Paul Ireland

It's very pleasing to have the following mappers confirmed to attend the White Lightening Mapwalk/Workshop so far… Wayne Aspin, Mike Beveridge, Paul Ireland, Carsten Jorgensen, Selwyn Palmer, John Robinson, and Graham Teahan. I hope you all got you Topic notes ok. Let me know if there is anyone else wishing to join in so I can print off enough workshop sheets for the day.

This is interesting. Or scary. The same piece of terrain as interpreted by 16 (Czech) mappers. Would we get that much variation throwing the Aspins, Teahans, MJW, Paul Ireland etc on to the same piece of dirt here?

http://peiza.kicks-ass.net/kartritare/

hopefully the maps would be finished

Very Scary indeed! I reckon less than half of the Czech fieldworkers in the above samples have produced a map which is up to scratch. With out seeing the terrain you can't say who is completely correct, but personally I like 'Martin's'style (the last one). He seems to have a good balance between too much small detail, and not enough, as some have done. His drawing is almost stylised to make the map visually asthetic and easy to read on the move. This is one point I brought up on our mapping workshop which no one seemed to notice, however we had very little time to discuss half the issues. Without going into detail, those of us at the workshop didn't seem to be too far apart in our interpretations. Some thought that I put too much detail on White Lightening in some places, others thought I didn't show enough in others. Often features were agreed worthy of mapping but there were two different camps of how to show it. The Czech exercise prooves that everyone eye sees the terrain differently, it can be as simple as looking at a contour height on a slightly different level. The most important things are that our choice of what to map and what to leave off is consistant and correct, and that it is in the right place, trying at all times to keep the map readable and clear. As Orienteers I think rather than thinking that the map may not have been perfect in your eyes we should perhaps focus on adapting and interpreting to the variety of mappers styles, after all, how else would you cope if you ran on all of the Czech maps on the above link?

Wow. I'm amazed at how different they all are. Really different. Even countour shapes are completly different, I expected vegetation but not everything. I'm also amazed how as an orienteer I look at different maps and think….that would be a cool place to race…or that looks easy. Interestingly I got both those impressions from the same area mapped differently. Maybe our easy maps would become more technically challenging if we over paid some mapper (I suggest Paul) with express insructions to over map?

Wouldn't we then need to get overweight orienteers to over run the controls?

Conversly, you could underpay some other mapper to undermap a technically challenging and interesting area. Only underweight orienteers would do well. Over running controls would become a thing of the past.

It would be interesting (to me anyway)to hear what your thoughts are on the various Czech mappers versions. To me Boris's is just wrong, Jans' is a jumbled mess, Pavel's seems all twisted like Neils brain, Milos clearly can't see contour shapes and should probably keep his day job and Tom is a real minimalist.

We have had under mapped maps and they are shit eg last years Nationals - bad idea

I have studied the Czech maps and it dosn't surprise me that Ales Hejna has the best result. After all he is the most experienced of all the Czech mappers. But lets have a good look at Martin's map since Paul seems to like it. Firstly, he has too many unnecessary formlines.For example at the Eastern part of the map there is a hill with a formline re-entrant on the West side. Why show the re-entrant? Everyone knows that a hill on a slope will form some sort of re-entrant on the uphill side, showing it with a formline as well ridiculous and only serves to make it harder to read the map. About the middle of the map there are some hills and knolls. Both Ales and Martin has shown the land form exactly the same but you only have to look at Ales's map for one second to get the information you need but on Martins map it would take longer to read the same details. The formline between the contours serves no purpose whatsoever. Martin has also got too many vegetation boundaries on his map. He has obviously not read the mapping specification regarding vege- tation boundaries within the forest. Many NZ forest maps have vegetation boundaries marked even if they are not distinct, let alone very distinct and on maps which has been enlarged 50% the black dots can be very confusing.

Hi Svend, you are more than likely correct about Martin's vegetation boundaries, and I completely agree with you that many NZ maps overuse them far too much. I also note that Martin is the only mapper to show a ride near the south east which suggests that he has overmapped this. I also find Ales's map very good in most aspects. Overall it is simple to read and uncluttered. My preference for Martin's map comes mainly because of the impression of land shape that he has created by closing contours together more on the steeper slopes and his precise use of form lines for the same reason. I felt that in a couple of areas Ales's formline contours were not serving much of a purpose as you have thought about Martin's map. With the knoll area on the hilltop I note that several of the other mappers have put in depressions here so although Ales's map is easier to read it may not be correct here. The reentrant that you have highlighted as totally pointless is more of an issue with me as it is one of the reasons I didn't pick Ales's map as my preference. I know this is one of your pet hates as I remember you talking about it on another occasion. Yes Martin's looks like an unneccessary extra, but if you look at the other mappers some of them have gone to the point of showing a depression in here, so there is clearly a deeper than would be expected reentrant between the hillside and the knoll. The thing is Ales hasn't even shown that small hill, or the knoll above it, or the big reentrant below it. At the bottom of the steep slope just below the rectangular vegetation boundary there is clearly a plateau, many of the mappers showed a huge depression here, but I find Ales's version a poor representation in this spot. I get a very clear picture along that whole easters slope with Martin's map that I dont get with Ales's. I agree mostly with your thoughts about the other unneccessary formline that Martin has shown in the gully on the western side of the hill, he appears to have got carried away with trying to show the steepness, but I really don't think it destroys the map either. Martin has shown more rocks, we can't debate these as we have no idea of their sizes. Half of the mappers have marked the distinct trees, half have not, either could be correct.

Does anyone know what sort of reputation Martin Telecky holds as a mapper in that part of the world?

Here's my two bobs worth of comments.

Most of the maps are perfectly fine for Orienteering on. Most have some good points but all have areas which you could criticise and/or are wrong in places. I'm usually the worst critic of my own maps.

For example, I find Ales's map a bit too generalised for my liking. I really don't like the double formline in Martin's map and the use of multiple formlines makes the map a bit cluttered for my liking.

The best map would be if you could all combine the correct and best features of all the maps and create an average montage - this would be like mapping by committee or consensus. You can do this if you have time for a major event. We did this for WMOC2000 as we had several mappers with similar styles and the controllers and planners had plenty of time to ask me to fix up problems for areas which were undermapped/overmapped.

Surely you cant tell without actually going there.

You can tell some features are wrongly mapped by comparing the maps against the others.

If most of the mappers had a feature in a certain spot and one mapper had it in a different spot then you would probably say that it has been wrongly mapped by that mapper.

Also, a lot of what we have been talking about is how a map is drawn, how a map is generalised and whether it is easy to read - a cartographer can tell just by looking at a map - obvious problems are breaks in contours, stacked formlines, overgeneralisation of a feature, invalid symbol sizes, too cluttered, overmapping.

Just another comment. I think that a lot of the differences in the maps could be due to a poor base map. There's nothing better than having a good accurate base map to start with and a clear aerial photograph - unfortunately this is not often the case.

Clearly they had quite a poor base map, I would say that here in NZ when we also get a poor base map we would get a similar wide variety of resulting maps. I think all efforts must go toward getting the best possible base maps to work with on all high profile mapping projects. One thing that was obvious on our recent Mapwalk on W/Lightning was that going over the completed map later with a blown up (larger scale) map, with the photogrammetry superimposed underneath made it very good and easy to see and make small changes here and there. Our fieldwork was done at 1:7500 by request as was the base photogrammetry, even though it is easier at 1:5000.

Interested in talking mapping on Sat night of QB vicinity Wellington? Focus on cartography rather than the field emphasis of Paul's mapwalk. Contact me at mapsport.co.nz

The IOF Map Commission has now published the evaluation of maps used for international events 2009 and 2010 including NZ maps used for Oceania Champs in 2009. The sprint map, Kairaki Beach, Craigieburn and Humpy Dumpy.

Do you have a link? - I can't find it on the IOF map Commission web site. What did the IOF evaluator say?

here is a link: http://lazarus.elte.hu/mc/evaluation/eva2.htm

http://lazarus.elite.hu/mc/index.html The evaluation was done by Sergio Grifoni. “Sprint map: Print quality looks OK, due to the fine colour dots. Symbols are in general correct with some mistake” (he mentions the green circle being the wrong size and something about contour and formline)

“Middle and long: Long at 1:10000 !!! There are three maps all at the 1:10000 scale. Two maps 4-colour offset printing. Printing very poor.” (I think he has that wrong) “One map (Kairaki Beach) 4-colour non offset: brown is close to be orange, so it is hardly readable on yellow and half-yellow. Besides, yellow is not according to specifications, and this fact makes the situation even worse. In rocky areas (Humpy Bumpy map) it is difficult to understand if boulders and cliffs touch each other or not. Since most of the map is yellow, it would have been better to use 75% yellow. Blue, green and yellow are not according to specifications, but reasonable. In one map there is a new symbol: 50% brown areas in the forest. Occasionally, two formlines between contours and some extra form line. A wonderful fieldwork wasted by poor printing and colour choices! Here again: did the Event Advisor accept the new symbol and the bad printing of Kairaki Beach and Humpy Bumpy?” My(Svend)comment: It must be remembered that Sergio Grifoni, in the past has got his evaluation wrong. A few years ago he criticized two european maps produced by two well-known mappers. Both maps and SG's comments were soon removed from the IOF Map Commissions web page.

So what can we make of it? The map commission is consistent in its critique and recognizes several very common problems with maps all around the world. Some of them you would have to agree with, others may be a little contentious. If you download the 20+mb 2009 evaluations the commission is very critical of several highest level maps made by top mappers, so we are not alone. Breaking it down you get similar problems or issue repeating themselves in the quest for perfect conformity&

Colour: Adhering to the ISOM 2000/ISSOM colours appears to be a big problem, and you have to admit they are correct about the orangey coloured light brown contours on Humpty Bumbty and the dark orangey yellow open areas on Kairaki Beach. Ive noticed that on a lot of our maps. I have no idea how this has come about but I do know that often I get a map file and the colours have been altered to suit a particular printer. Problem is that the master file is not put back to normal. Really the master copy should never be altered. Some clubs are probably good with this, others are fairly blasé. We really need to get more involved with our printers to ensure we get the right colour palette.

Symbol Sizes: Is another common complaint from the map police. Some of their discoveries were indeed quite bad, others very minor. With some objects I wonder if a problem that was not there with the old specifications, has actually been created by an increase in size going too far, hence it almost becomes common practice to stray away from the correct size.

Paper Quality: Seems to come up a lot, and it always will until we find and settle on a small choice of papers and thicknesses. They didnt like it when the paper was too thick either. Ive noticed that very glossy papers, although they are good quality and print nicely, tend to be the ones which fail the quickest at the creases.

Form lines: Too many unnecessary ones is another common complaint. Strangely where they picked on some of the Swiss maps quite a lot, I felt mostly that they did show additional useful information. But yes there were some useless ones. A very common criticism of the commission was having two form lines between contours. This is supposed to be a no-no, but I can now see it actually happens more than you think. Ill have to admit that at times I am guilty. Problem occurs sometimes on complex terrain where no matter how you alter the above, the bellow, and the middle, you still need another to represent whats happening, and if you leave something out it is just wrong!

Generalisation: Always the big battle for the fieldworker, what to leave on or off, how to show it best graphically for legibility. Work in progress for everyone to be the perfect mapper. Small problem becomes a major if it is for a 1:15000 map!

Scale: Where do you start and finish with this issue? I can see why the attraction of 1:15000 for long distance, because they want to hold onto the traditional form of O in regard to long route choice legs and less complexity. But there are many problems and to me it comes down to having to purpose make a map intended for that scale. The same terrain used for a middle distance, and for the other grades would normally be at 1:10000 and by todays mapping standards would almost always need to be mapped at greater detail than for a 1:15000 map. No one wants to make two different maps of the same terrain. I think it needs to be remembered that it is also the runners job to simplify or discard detail when needed. It is part of the skill set. I think this also highlights that we should put more focus on good course setting for the appropriate format. Bring back the NZOF course setting competition?

So really the commission is doing it's job, which without it would be anachy. Not that I agree with everything but am at least trying. Hopefully some of the problems will be fixed with ISOM201X!

Our biggest issue to improve on is printing quality. That's my 2c

At a Norwegian map conference an exercise was set to map a nearby piece or urban terrain. Always good to see different approaches, here there were some issues to do with multiple levels (carparking building). This Attackpoint thread http://www.attackpoint.org/discussionthread.jsp/message_929383 has a discussion in English and links to the Norwegian website where the maps are.

Pretty much what I expected - the eight mappers only had an hour to map so what we are seeing is a first draft. Most of the maps would be ok to run on apart from the last which I think is too generalised. A really accurate sprint map only comes from lots of different versions and several different people (mapper(s), controller, IOF controller) all going out and making incremental refinements and discussing contentious areas and looking at control sites - something only done for large events. Split levels are a pain - some levels on the Oceania/World cup maps went through 15-20 different versions before everyone was mostly happy.

Announcing OcadDiff - a small tool too visualize changes between Ocad files http://blog.yannisguedel.ch/2015/08/17/announcing-ocaddiff-a-small-tool-too-visualize-changes-between-ocad-files/

Oh, this is my effort on the diff front: http://miettii.net/post/producing-comparison-maps-with-ocad/