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In fairness, the vast majority of the models of the earth people use day-to-day are flat. Case in point: https://www.google.com/maps/@43.0279156,-94.0814245,3
by 13of40 11y ago
In fairness, the vast majority of the models of the earth people use day-to-day are flat. Case in point: https://www.google.com/maps/@43.0279156,-94.0814245,3z https://www.google.com/maps/@43.0279156,-94.0814245,3z
- Double_Cast 11y agoxkcd relevant to this thread. https://xkcd.com/1318/ https://xkcd.com/1318/
- pdonis 11y agoThis doesn't model the earth's surface as flat. It uses a distorted flat map to model the actual curved geometry of the earth's surface. If the earth were actually flat, the flat map wouldn't be distorted.
- 13of40 11y agoMy point is that Google Maps is possibly the most widely used model of the earth we have, and there's no use case for it where the curvature of the earth comes into play.
- Natanael_L 11y agoThe projection chosen IS the model, and we chose a useful one - and that projection is flat. Is paper maps not models of the real world?
- pdonis 11y ago> The projection chosen IS the model Not if you're going to say the projection is flat. If the projection is flat, and the projection is the model, then I should be able to lay a flat ruler, appropriately scaled, between any two points on the flat map and read off the actual distance between those two points. But I can't do that; and the model knows I can't do that. The model tells me to take the coordinates on the map of two points and plug them into a complicated mathematical formula if I want to get the actual distance between them. So the model is not flat in the sense that matters--in the predictions it makes for distances between points.
- zardo 11y ago>Not if you're going to say the projection is flat. If the projection is flat, and the projection is the model, then I should be able to lay a flat ruler, appropriately scaled, between any two points on the flat map and read off the actual distance between those two points. Is a constant distance metric part of the definition of flat? Why don't the grid lines on the map count as an appropriately scaled ruler?
- pdonis 11y ago> Is a constant distance metric part of the definition of flat? Yes. Otherwise "flat" would have no meaning; we can always make a flat map of any surface, if we are willing to allow the distance metric to be distorted to any extent we like, so every possible surface would be "flat".