4 ms·
Subway "maps" tend to be more like generalized graph diagrams than cartographically accurate maps. After all, you're stuck in a box and your only choice is whic
by marshray 15y ago
Subway "maps" tend to be more like generalized graph diagrams than cartographically accurate maps. After all, you're stuck in a box and your only choice is which node to get off at.
But it wouldn't surprise me if an overlay on a cartographic map was intentionally inaccurate. One time I was in DC a cab driver was trying to get me to my hotel. His GPS went totally nonfunctional when we were in view of the Pentagon.
It would be an interesting research project to ride around subway systems with a data-logging accelerometer (like a smartphone). Integrate acceleration to get velocity, integrate velocity to get relative position, get GPS fixes when the signal is available, and diagram the results.
- georgieporgie 15y agoHis GPS went totally nonfunctional when we were in view of the Pentagon. Which is pretty humorous since, once you're vaguely close to it, it's hard not to find it. If they built several other pentagonal buildings in the area, it would be a different story. :-)
- Game_Ender 15y agoThey might have some local GPS jammers to make it harder for unmanned drones or bombs to navigate near the building.
- nkassis 15y agoInteresting, I had someone report something similar next to the Canadian SIS building in Ottawa. His GPS was telling him the completely wrong route. I don't have a GPS personally to try it.
- colanderman 15y agoIntegrate acceleration to get velocity, integrate velocity to get relative position, get GPS fixes when the signal is available, and diagram the results. Sadly integrating "real data" even once results in wild inaccuracies. A small error in acceleration turns into an offset in velocity which turns into large position drift over time.