[Openstreetmap] the disappearing landsat and speedups

[SteveC]

onearth, the JPL provided landsat imagery has dropped off the net and so
openstreetmap doesn't currently look great.

various speedups have gone live

* tile creation uses Magick instead of Cairo so it doesn't have to save
  the tile to disk and then spit it out. Also, projection calculations
  are re-used. munin says this takes less memory and creation looks
  quicker
* tiles that are too big or cover too large a section of the planet just
  return a blank (transparent) streets or gpx layer rather than kill the
  database
* load statements have been replaced with require so mod_ruby doesn't
  re-read libraries on every hit

have fun,

SteveC steve at asklater.com http://www.asklater.com/steve/