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"For anyone else utterly confused about what the heck "grid north" is" What you seem to be pointing out is a lack of familiarity with real, paper maps or carto

"For anyone else utterly confused about what the heck "grid north" is" What you seem to be pointing out is a lack of familiarity with real, paper maps or cartography in general. Apps don't seem to bother with grids. Anyone who has used a paper map in anger would probably get the idea intuitively without it being spelled out. When the battery is fucked on your phone, you'll be damned glad of a map folded ... map when you're bimbling across a moor. Anyway, we live on an oblate spheroid with extra bumpy bits and any attempt to model it in 2D is always going to involve some imaginative shortcuts and a lot of papering over the cracks. Trying to define a datum or a direction on this thing is a bloody nightmare. Height/altitude is just as weird ...

crazygringo 4y ago
Not really. I certainly used paper map atlases for city navigation pre-smartphone, and I've done my share of cartographic projection plotting. But "grid north" doesn't refer to any specific direction, in the way true north and magnetic north do. It depends on the projection, but the headline implies a single "grid north". Hence why it's confusing. (In this case it assumes knowledge of a particular official local projection.) Whereas by point of comparison, online maps generally use Mercator (technically "Web Mercator") for local navigation, where there is no distinct "grid north". Up is always true north in standard Mercator.
- gerdesj 4y ago
  It's been a while since I unfolded one but I have a fair few Landrangers etc on the bookshelf. On OS (UK - Ordnance Survey) maps, there is always a set of three arrows that show grid/true/magnetic north. I suspect that most countries will have a similar system. When you consider how hard it is to represent geography and direction on paper, a localised grid is an obvious starting point. I am pretty sure that all countries will have their own version of grid north, just as they have a mean sea level(s). In the UK we have mean sea level in Cornwall, specifically in Newlyn harbour under a small hut. Bit odd but no odder than most countries that also maintain a sea level datum, which is pretty much all of them. Some have more than one and in some really strange places. The world is a really odd shape! Mercator is a projection, ie a method of how to make a 3d thing into a fairly useful 2d model of the 3d thing. No idea what a web Mercator is but I doubt the Flemish bloke minds too much. As you imply Mercator does preserve "north" but it is curved in that projection so not "up", unless you allow for "up" to be a curve.
  - eru 4y ago
    > Bit odd but no odder than most countries that also maintain a sea level datum, which is pretty much all of them. I wonder whether Czechia, Switzerland and Austria bother?
- chrisseaton 4y ago
  > but the headline implies a single "grid north" All countries have a grid system though?

crazygringo 4y ago

Not really. I certainly used paper map atlases for city navigation pre-smartphone, and I've done my share of cartographic projection plotting. But "grid north" doesn't refer to any specific direction, in the way true north and magnetic north do. It depends on the projection, but the headline implies a single "grid north". Hence why it's confusing. (In this case it assumes knowledge of a particular official local projection.) Whereas by point of comparison, online maps generally use Mercator (technically "Web Mercator") for local navigation, where there is no distinct "grid north". Up is always true north in standard Mercator.

gerdesj 4y ago
It's been a while since I unfolded one but I have a fair few Landrangers etc on the bookshelf. On OS (UK - Ordnance Survey) maps, there is always a set of three arrows that show grid/true/magnetic north. I suspect that most countries will have a similar system. When you consider how hard it is to represent geography and direction on paper, a localised grid is an obvious starting point. I am pretty sure that all countries will have their own version of grid north, just as they have a mean sea level(s). In the UK we have mean sea level in Cornwall, specifically in Newlyn harbour under a small hut. Bit odd but no odder than most countries that also maintain a sea level datum, which is pretty much all of them. Some have more than one and in some really strange places. The world is a really odd shape! Mercator is a projection, ie a method of how to make a 3d thing into a fairly useful 2d model of the 3d thing. No idea what a web Mercator is but I doubt the Flemish bloke minds too much. As you imply Mercator does preserve "north" but it is curved in that projection so not "up", unless you allow for "up" to be a curve.
- eru 4y ago
  > Bit odd but no odder than most countries that also maintain a sea level datum, which is pretty much all of them. I wonder whether Czechia, Switzerland and Austria bother?
chrisseaton 4y ago
> but the headline implies a single "grid north" All countries have a grid system though?