Hop over to Sky Pilots
and follow along as we make an orienteering map!
We're now on post number 2 out of (probably) 10. Posts will keep coming every three days until we finish.
Participation, comments, questions, feedback, criticism, and advice are all welcome!
Third post is up: Contours!
Looks like a great project with lots of info.
Wouldn´t be completely transferrable to Swedish mapping though...
Eric, I'm curious, how much mapping experience did you have prior to this project?
What a detailed description of the process you're using!
By the way, I don't think you should create / use a special symbol for fallen trees.
Fascinating detail. Thank you.
I can't help thinking, however, that there are simpler ways of getting from A to B.
Why not start the map with an import of the area from Open Street Map? It will give you an already-georeferenced start to the map.
Don't worry if the map boundaries are larger than you want them to be. The map can always be trimmed later.
Given the choice of enlarging the map scale or putting on a legend, I vote for the larger scale every time, legend for special symbols only. The symbols for orienteering maps are the same wherever you go in the world. It is good enough to have some symbol sheets available for the few who need them.
Contour interval? If you want a 5m final interval I think it is reasonable to also import a full set of 2.5 m form lines with a view to keeping the segments that prove to be useful and discarding the rest. Some might even recommend 1 m form lines for the draft map.
Thanks to everyone for the comments so far!
bubo: Sorry that the tutorial is a bit US-centric! Our club membership is spread over several states in the western US. I see that data sources would be different in other countries. Is there anything else in the process that you think would be vary by country, or for Sweden specifically?
Canadian: My wife and I (it's a team effort) consider ourselves learners. We've had to teach ourselves using some of the resources already out there and a ton of trial and error.
We've previously tackled a couple projects in California for fringe off-the-radar events you've never heard of (orienteering-style maps for non-standard events).
Since moving to Colorado, we've completed one medium-size project (1200 acres) and are partway through a really big one mapped at 1:30,000 for a 24 hour event.
With snow now hitting that area, we wanted to work on something lower and smaller, hence the current 200 acre project. It occurred to us that we should document the process to make it easier for anyone else trying to learn.
The level of detail is possibly excessive, I know.
It partly comes from the fact that I tend to forget things if I don't write them down. But there are a couple of other factors.
First, our small club includes some folks that have expressed interest in map making, and not all of them have a strong background in computer applications. In my previous life, I've had to write technical instructions for non-technical people.
The second thing is that I've already seen several prospective mappers hit a major obstacle at contours and then get discouraged. If we can get people past that hurdle, things get a lot easier and the level of detail can maybe ease off.
Fallen trees: I've seen the symbol used to good effect on several maps in California. It's basically a more explicit version of the old rootstock symbol which shows not just position and orientation but also extent. It makes sense for an isolated huge redwood that is going to lay on the forest floor in much the same state for the next hundred years. But I'll agree that it can be problematic and is not appropriate for every area. For what it's worth, for the current project, we've already concluded that the symbol is not helpful.
gordhun: Thanks for the detailed comments.
Open Street Map is interesting. It's not a resource I know much about and will have look into it. I'm especially intrigued by the apparent ease of georeferencing.
Good advice on the other stuff too. For contours, I normally like to do what you describe, but for this project, the source data just doesn't have sufficient resolution for those additional lines to be trustworthy or meaningful. Even the 5m lines are in need of correction, sometimes woefully so.
I'm always interested in learning about mapping efforts. Thanks for sharing all your resources Eric!
Fourth post is up: Armchair Mapping
Learnt something... drafting on Google Earth and then importing as an alternative. Thanks.
Thank you for these weekly postings. I'm looking forward to your reports on field checking such a beautiful area. Will you be taking a tablet in the field or going old school? I'm anxious to find out. (I'm a hybrid of the two using Mylar and colored pencils along with a gps watch.)
In the meantime I invite you to check out a similar but far less comprehensive report I did on building a map using OCAD 2018.
An important key to simplifying the process is to have LiDAR available in ,laz files. Your county, Ouray County CO, does not have them on the USGS site so your use of the 1/3 arc data is very informative for me.
That gives impression the area in question was scanned 2018
I didn't try downloading it since it is 102 GB
Day 5 of our mapping tutorial is complete. First day collecting data in the field.
I'm too tired right now to answer some of the newer comments, but thanks, I'm glad to learn some new things and will look closer tomorrow!
I guess three are two ways to approach and carry out the fieldwork.
One is block by block as you are doing.
I prefer the Christmas tree approach. The name comes from how our family used to decorate our tree putting on the strings of lights and streamers (I forget what they are called) first then the bulbs and other single decorations finishing with the tinsel.
So to me the trails, fences, streams and other linear objects are the lights, etc. I get them done first.
Then I go back and do the point objects and lo and behold I have far more points along trails, fence corners, etc. to use for triangulations and other references.
That is not to say I would ignore a point object if it were easy to get while walking the trail.
I hope you are enjoying your mapping as much as I am enjoying the photos of your beautiful area.
Logging point and line features and adding them afterwards will work for terrain with sparse mappable features. In more densely featured terrain the act of drawing reveals to me the need for additional generalization, exaggeration and drafting compromise. I don't feel comfortable making those decisions once I am back at the desk. With a tablet I can sort those issues out with the terrain in front of me. Every day I spend dealing with these issues increases my respect for the previous generation of mappers working with mylar and pencils.
This is an incredible read. Thanks for sharing your efforts--I'm always curious to see what goes on behind the scenes.
To Inv Log's point about the importance of drawing in the field (tablet or pencils), I'd like to add an even more fundamental reason: that is simply getting the features in the correct relative position to each other.
A lot of techno faith based mapping assumes that if the GPS is rated to X meter absolute accuracy, that the resulting relative accuracy will follow. There are a multitude of reasons why that doesn't work out in many (most?) cases.
The technology, and skills to apply it correctly vary dramatically, to say nothing about terrain/forest/vegetation conditions, or day to day variations related to satellite positions.
It doesn't take much of an error for a point feature to end up on the wrong side of a linear feature, to say nothing about more complex relationships.
I've seen some logged (remote drawing) mapping of average detailed areas that was OK, but plenty (most?) of what I've seen is not.
Agreed, the less detailed the area, or map, the better the chances of satisfactory results. Rogaine maps are a good example.
To Gord's point about Christmas tree mapping, I'd like to add a cautionary point for beginner mappers.
I've seen too many cases where this approach was applied, or at least attempted, and failed.
This is very appealing, more like seductive, for a first timer. The problem is they eventually get a large chunk, or even the whole area covered along the trail network, but never actually get into the terrain, and learn complete mapping. The job is too formidable, the project, abandoned, and a potential mapper, lost.
Yes almost all mapping comes down to a combination of the two forms Gord describes. You need to establish known locations around an area before filling it in.. The variable is the size of the block.
For beginners, I think the best advice is to keep the blocks small, and learn to fill them in from the start. Maybe some outside feedback or redoing is involved, but learn to do complete mapping, not how to procrastinate it.
Clearly the Christmas tree approach works for Gord. He has no problem completing projects. On the other hand I think other successful mappers move so smoothly through a block-by-block style that they practically defy the term.
First up, anything I have said and continue to say should not be construed as criticism of this really interesting exercise in sharing mapping approaches. I have learnt a few new tricks.. particular the use of Google Earth for drafting visible features. I think the approach used for the example is probably quite suitable... horses for courses. The sort of terrain I was thinking of in my comments about data logging is this.
I would make a distinction between tablet and pen and paper/mylar. Faced with this terrain, the main decisions are often what not to map. My aim is to comply with the minimum separations specified in the ISOM. When using pen and paper I find it all too easy to draw symbols smaller than the specification to fit more in. Its often not a conscious decision. When I am drafting on the desktop I discover I have to change the interpretation of the terrain based upon memory. Hats off to those with the skill not to fall for this trap. I am not experienced enough to trust myself. The tablet forces me to confront legibility issues whilst in the field. Like I said previously, I have growing admiration for those mapping terrain such as Mt Kooyoora using mylar and drafting pencils.
Re GPS accuracy... real time correction is now an affordable option.
IMO for block-by-block style mapping the GPS accuracy is just fine. You locate a feature, you stand by it for a while and let GPS settle and map it with your tablet. And then an other feature ~40 m away. maybe tirdd again 50m away to make it a triangle. All features in between you place relatively to those gps measured ones (not by making more gps measurements). You never gps measure two features too close together. Like this some meters of GPS error doesn't make any difference, error isn't any bigger than position errors we make for legibility/generalization.
Edit: I think the way Gordhun does his hybrid Christmas tree style effectively does the same, GPS measured points here and there and the rest is triangulated based on those. It doesn't matter is it block-by-block or whatever as long as you know what you are doing and why.
Back in the days of photogrammetric base maps, there was a built-in mechanism to keep people with pencils and mylar from squeezing in too much detail. The basemap was delivered at (typically) 1:7500, and there wasn't a good practical way to change that. So all fieldwork happened at that scale, and there's a limit to what you can draw with 0.5 mm pencils. These days it's trivial to print the basemap at any scale you like.
This is some really valuable discussion!
What an eye-opening map that TheInvisibleLog posted.
The area for this project isn't incredibly dense, but does have plenty features that are too close to blindly trust GPS.
Even a boulder on the side of the trail or stream needs a note about which side. I don't really draw in the field, but we do make fairly extensive notes about relative locations. Of course, sometimes we get home and realize that a spot can't be drawn to scale and has to be generalized, so a lot of those notes are wasted.
I can see that I have a lot of leads to follow up and learn from!
By the way, the mapping project itself is now complete. It's just the write up that is now lagging. We are going to have a club practice session on three courses next weekend to test the map.
So do you want another project?
I suggest Electric Hills on the west side of Montrose CO. It looks pretty good.
To make live gps tracking, post race analysis / visualizations easy to do it is important to not let map get skewed / distorted much. I have lately been doing 3D videos of my O runs and it has been revealing - all lidar based maps are fine (even if I just scan my paper map like yesterday's run https://youtu.be/HVclAIRW9Ig
), but even if gps track can be tweaked easily to match anyhing it is often almost impossible to make older photogrammetry based maps match with DEM landforms. Missplaced hilltops and big cliffs look pretty bad. Sure, these are less important but still worth mentioning.
Jagge, that 3D video of your O run is super cool. It would be a great tool for orienteers, coaches, course planners, and the like.
The viewer doesn't care where the data is from, but the app that makes the 3D scene is currently Finland only. Because the lidar source service it uses has laz files from Finland only. Input is a georeferenced map image or a gpx track file (MapAnt.fi map is used as a map), it downloads correct tiles, processes for couple of minutes and spits out a folder to be viewed in the 3D viewer. I guess it would be possible to make simple less automatic version, user would need to download laz files and take care of coordianate systems.
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