1. 05 Oct, 2012 3 commits
  2. 04 Oct, 2012 1 commit
    • Jason Davies's avatar
      Better resampling for non-linear distortions. · 427c02c3
      Jason Davies authored
      I've reinstated the original conditional for linear longitudinal
      interpolation, since the x * x < ε conditional was not tight enough and
      hence caused glitches in projections that include the poles e.g.
      stereographic.
      
      Back to solving the issue that was primarily noticeable in the Albers
      demo: graticules near the poles would not resample correctly. We made an
      assumption that a point mid-way along the connecting great arc is going
      to be approximately mid-way in pixel-space. This is a reasonable
      assumption in most cases, but there is an area of high instability near
      the poles, since a small change in distance could result in a large
      change in longitude, e.g. imagine a great arc going right over a pole,
      so the longitude will change greatly depending on which side of the pole
      you're on.
      
      So the new fix is to see if the distance in pixel-space hardly changed
      at all, and in this case we attempt to interpolate again, mid-way to the
      new spherical coordinates. I think we can probably improve this even
      further by borrowing methods from standard root-finding techniques e.g.
      Newton-Raphson.
      427c02c3
  3. 03 Oct, 2012 3 commits
  4. 02 Oct, 2012 19 commits
  5. 01 Oct, 2012 3 commits
  6. 29 Sep, 2012 11 commits