PDP Gimp Scripts
You can either clone the git repository, or if you are just interested in using the scripts (without modifying them), simply download the SCM file(s) and move them into the directory that your Gimp/Preferences identifies as your Scripts folder.
From there, you can find the menu item in Image/Resample.
Written for GIMP 2. Tested on GIMP 2.6 for Mac and Windows and GIMP 2.8 for Mac and GIMP 2.8 Portable for Windows.