I am trying to use GPS lat/long coordinates for dataviz stuff and:
Mapping GPS data to a vvvv-globe: Cartesian (3d) check
Mapping GPS data to a local map: Map (Value) check
but I have been trying for hours now to consistently put coordinates in their right places on a large map - of the US - but no dice. There’s always an offset - bigger when going north. I uderstand why but I don’t understand what I could do about it.
Has anyone experience with this?
Cartesian (3d) only maps lat/long on a sphere, which is not quite correct when it comes to cartography. earth is an ellipse, so most worlmaps use mercator projection with the WGS84 ellipsoid. you can find loads of conversions on the web.
however when it comes to maps of countries, the possibility is high, that a completely different projection is used, e.g. lambert conic.
so you need to know exactly what projection is used for the map you have to be able to get precise lat/long conversion
I figured I could just(?) use a Mercator projection out of the box but especially for the US, Mercator is butt-ugly :) Seems like it’s Lambert conic indeed. But I haven’t looked deeper into this so far (just some “in light of recent events” procrastination upon finding extensive US shooting statistics…)
Was just wondering whether someone had dealt with this before. But I will very likely revisit the idea, so your tips (the contribution!) are much appreciated.