title: variogram range is not unique within some specific degree
body: <p><a href="https://i.stack.imgur.com/LTjIs.jpg" rel="nofollow noreferrer">variogram of the dataset</a></p>
  
  <p>I got this variogram from a set of spatial temporal data, but i am wondering why the 90 degree have such a 'small' range compare to other, is it my data problem or I can adjust some setting in the </p>
  
  <pre><code>v&lt;-variogram(Thickness~Age+x+y,data,alpha=seq(0,135,45),beta=seq(0,45,45))
  </code></pre>
  
  <p>Any suggestion? Thank you</p>