Occassional thoughts about orienteering

Tuesday, October 15, 2002

Map scales - 1:10,000 v 1:15,000


The Southern Michigan A-meet used 1:15,000 maps for the blue and red courses and 1:10,000 for all other courses. The maps appeared to be color copies of ink jet prints.

Comparing the two versions of the maps was startling. The 1:10,000 maps were much more readable. Some features were much easier to read on the 1:10,000 version. For example, the small tick marks on depressions stood out clearly on the 1:10,000 map and were difficult to see on the 1:15,000 map.

I asked some of the SMOC members why the blue course didn't use a 1:10,000 map. They said that USOF either told them they couldn't or suggested that they shouldn't. I'm not sure who "USOF" would have been - maybe the sanctioning committee or maybe the course consultant.

I wish we'd had the 1:10,000 version of the map and I can't understand why a 1:15,000 version would be preferable.

I discussed map scale with a few people at the meet and got a few lame arguments for 1:15,000:

1. A 1:10,000 map is too big a piece of paper -- it is hard to carry. That seems a bit ridiculous. You can always fold the map in half (don't blue course runners know how to fold the map?). At SMOC the blue courses could have been printed at 1:10,000 on an 8 1/2 x 11 inch piece of paper. I've never heard people complain that a 1:15,000 map is too big. We've orienteered on some big pieces of paper: Silvermine and Surebrigde Mountain are good examples. Have people complained that the paper is too big?

2. Using a 1:15,000 map is good because top elite races use 1:15,000 maps. The concept seems reasonable....except it isn't correct. The last WOC used maps at 1:10,000, 1:5,000 and 1:15,000. The European Champs used maps at 1:5,000, 1:10,000 and 1:15,000. The top elite races force competitors to use different scales in a relatively short period of time.

3. Some people have difficulty adjusting to "different" scales (i.e. if they're used to 1:15,000 then it is hard to use 1:10,000). I'll buy that it might be true. But, it doesn't seem like a good reason to stick with a specific scale.

4. 1:10,000 maps are over detailed because the mapper squeezes too much detail into the map. The level of detail is more a function of the scale the fieldchecker works at than the scale the map is printed at. Maps fieldchecked at 1:7,500 or 1:10,000 aren't usually over detailed.

5. Course setters tend to set fewer long legs on 1:10,000 maps than on 1:15,000 maps. That's finally an argument I buy (at least a bit). To me, the harm of fewer long legs is less than the harm of making it hard for orienteers to read the map.

The argument for using 1:10,000 seems stronger -- the map was much easier to read at 1:10,000. Orienteering is about using the map to navigate. It shouldn't be about testing eyesight and individual abilities to make educated guesses about features that aren't clearly shown.

I don't think I suffered from the 1:15,000 scale map. I carried my magnifier and was able to read details fairly well. In fact, the hard to read map probably helped me (because I carry a magnifier).

If the map had been offset printed, 1:15,000 would have been fine. But, it wasn't. Maps printed on ink-jet printers are not as easy to read as offset printed maps.

posted by Michael | 7:46 PM


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