overviewer/Minecraft-Overviewer — pull request #1055 by PIBM (2014-01-20 20:39:21+00:00)
Title: Prevent opening and parsing files which haven't been modified since the ...

...last time that the render was done.

On a large world, that cut the scanning time from approximately 25 minutes to 1 minute. Renders weren't affected beside being faster.