title: SpatialPoints and SpatialPointsDataframe
body: <p>Working with the <a href="https://cran.r-project.org/web/packages/sp/sp.pdf">sp</a> package in R. 
  I wonder when I would use SpatialPoints and when SpatialPointsDataframe. It seems so me that there is not much difference?!</p>
  
  <p>Is the only difference that in a SpatialPointsDataframe I can store more attributes?!
  If so, can I create a SpatialPointDataframe from an existing Dataframe (if coordinates are exisiting in this dataframe) without taking the detour of creating spatialPoints?</p>