title: How to change the resolution of a raster layer in R
body: <p>I have several high resolution raster layers in R that I am working with. The level of detail is excessive for some of the analyses I am running, so I would like to speed things up by reducing the resolution. </p>
  
  <p>The coordinate system is UTM so the units are meters. The resolution says it is 30, 30 (x, y). So it seems that the resolution here is 30m. </p>
  
  <p>Could someone please advise me on how to change the resolution to 120m instead? I have read the help for the resample() and projectRaster() functions but they seem to require a template raster with the desired resolution, which I don't have.</p>
  
  <p>Here is an example of one of my raster layers:</p>
  
  <blockquote>
    <p>alt.utm<br>
    class       : RasterLayer<br>
    dimensions  : 4572, 2495, 11407140  (nrow, ncol, ncell)<br>
    resolution  : 30, 30  (x, y)<br>
    extent      : 421661, 496511, 4402939, 4540099  (xmin, xmax, ymin, ymax)<br>
    coord. ref. : +proj=utm +zone=13 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs<br>
    data source : in memory<br>
    names       : layer<br>
    values      : 1485.127, 4275.202  (min, max)  </p>
  </blockquote>