Discussion: MN line spacing--does it matter?

There is a lively debate in our household, to be settled by the high court of Attackpoint public opinion. What could go wrong?

1. Does it matter if the magnetic north lines on an orienteering map are NOT at the specified spacing (300m for forest maps or 120m for sprint maps)?

2. Does anyone use that spacing explicitly or subconsciously to help them navigate--estimating or measuring distance? Have you been thrown off by that during races?

Background:
Since ISOM 2017, the MN line spacing "shall be...300m on the ground..." This is the (foot-O) forest mapping standards for scales: 1:15,000, 1:10,000, 1:7,500, 1:5000. Prior to that, the ISOM 2000 standards called for 500m spacing on 15k maps, and round number spacing at other scales. 250m was typical.

Since ISSprOM 2019 (in effect starting Jan 2020), the MN line spacing "shall be...120m on the ground..." for sprint maps. This is the sprint mapping standard for scales: 1:4,000 and 1:3,000. Prior to that, ISSOM 2007 called for 150m spacing for both 1:5,000 and 1:4,000 scales.

Although not hard to "fix" on older maps, "grandfathering" 250m MN lines seems reasonable for training and local competition. Is it (or should it be) required for national-level (or above) competition--"sanctioned" races in OUSA terminology?

I think they should adhere to the spec, though admittedly when setting local/training courses on older maps with other spacing it does not occur to me to fix them, though it would be a fairly simple thing.

I don't use the spacing to estimate distance when running but since a specific spacing is given, it should be adhered to.

The MN lines need to be close enough to each other for at least one to be under a compass when a bearing is being set.

Used to be there was some level of grandfathering as a given since we were working with a supply of already offset-printed maps. I think for local events it's completely reasonable to act as if that were still what's going on. For sanctioned races, it's probably worth the effort to fix things up to the spec, and for maps that are used frequently, they might as well be updated as well.

The more important thing as far as I'm concerned is that they should be close enough that at least one line falls under a typical compass capsule no matter where you put the compass on the map. The failing is when you have a 1:10000 map that's an enlargement of a 1:15000 that had 500 m spacing, and the lines are too far apart (or the same deal with other scale translations).

If we are counting votes then I vote for J-J.

Orienteering is already too easy. Maps should have grid north lines rather than magnetic north to make runners have to offset all bearings whilst on the run.

Down vote for TRicky........Up vote for JJ....I would add that no matter what the spacing, a scale should be shown between the lines to confirm what the spacing is. I do occasionally use the spacing as a rough guide of distance.

That is a trivial issue.

By far more important is that all the names of trails , swamps, lakes, roads ("Happy Trail", "Murky Swamp", etc) are printed right there next to or over the object, oriented in the direction of the trail/road, and not east-west.

Yurets is right, its trivial to most. Having gotten very used to 250 and 150, I personally much prefer those. Personal opinion aside, we really should follow the specs for national events, which reminds me that I have to re-do the north lines on the maps for this year's Flying Pig since they are older maps.

To me, a MUCH bigger issue than the spacing of north lines is those maps where mag north is not aligned with the paper edges, control numbers, and other text. On such a map, I tend to get thrown off no matter how the north lines are speced. The paper edges probably matter a lot less than orienting all text and control numbers to mag north.

Yep. I've drafted a few maps that had to be at an angle to fit on the available paper, and there's a right way to do it. All text on the map is oriented to magnetic north. This includes the roads that form the borders of the map (I keep those oriented to mag north no matter if the map is rotated or not). The only thing that's not aligned to magnetic north is the edges of the paper, and those disappear when you fold the map.

The craziest nightmare map I ever saw was at the 1991 US Relay Champs. The well-meaning but misinformed course setter had printed the courses so that every control number was right side up when you were holding the map such that the control in question was at the top. So the control numbers were all at random angles. Aieeee!