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ROGUE-JCTD / Grout

MIT License
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non-spherical mercator support as a goal #5

Closed bradh closed 5 years ago

bradh commented 12 years ago

If I understand your proposal, tiles are square in pixels, and in coordinate extent

How is that going to work with anything except spherical mercator?

pepijnve commented 12 years ago

What issue do you see here? If a tile is square in pixel coordinates and it's spatial extent is a square in spatial coordinates then the pixels are square in spatial coordinates as well. I don't see how this is restricted to web-mercator.

bradh commented 12 years ago

I couldn't see how the spatial extent would always be square in spatial coordinates. You are right that I should have pointed out examples like polar projections rather than anything-"not spherical mercator".

pepijnve commented 12 years ago

By spatial coordinates I mean the projected CS; not the underlying geographic CS. In polar stereo, or any other projected CS, you still have a cartesian system with an orthogonal easting northing axis. Why could you not define square tiles in that?

antinodes commented 12 years ago

I did the math before posting and double checked using qGIS (I wasn't convinced everything work "just work" either). Using a Polar Azimuthal Equidistant projection the math all still works. The units are all meters and the origin is at the pole.