title: How to resample a raster snapping to an existing grid?
body: <p>I would like to resample a raster from a high resolution to a low resolution (with different extent) in a defined grid cell. Is there a way of using an existing raster file as input for the snapping?</p>
  
  <p>In the raster package, <code>aggregate</code> and <code>resample</code> seem to be adequate but I can't find how to do it.</p>