title: fitting Poisson GLM model for a very large spatial data set
body: <p>I have a data set including "longitude", "latitude" and "month" of points (events). I converted points into SpatialPolygonsDataFrame with size 1km*1km. Then I counted the number of points in each grid as a dependent variable ("Freq"). </p>
  
  <p>Now, I want to fit GLM. but I don't know whether is correct if I consider "longitude" and "latitude" as predictors. </p>
  
  <p>My code for this looks like below:</p>
  
  <pre><code>fit = glm(Freq ~  longitude + latitude + month , family=poisson(link=log), data=events)
  </code></pre>