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Why not signed?

• geokon 5y ago
  yeah, good question. My limited experience has shown me that you end up coding in assumptions that make the sign flip problematic :). There are all those infamous cases of systems crashing on planes and ships when they cross the equator. Ideally you'd test in all four quadrants of the globe but this ends up being cumbersome. There is also the convenience of having your coordinates change in the same way as your display coordinates. So if something displays off of where it should then you can easily diagnose the problem. Everything is always in units of degrees relative to the top left corner (with maybe a scale factor) - whether you're looking at the whole globe or just a region. With a signed coordinate you'd be relative to the image center which is not how your display works. You need to track offsets and image widths/heights. Debugging gets nastier and you have off by one problems and whatnot. That's just been my experience so far
  • iopq 5y ago
    That's what I'm saying, you map the negative latitude and longitude to negative numbers