title: Why does interp function give me error?
body: <pre><code>n &lt;- akima :: interp(
              x, y, z, xo = seq(min(x), max(x), length = 100), 
              yo = seq(min(y), max(y), length = 100),
              linear = TRUE, extrap = FALSE,
              duplicate = "error", dupfun = NULL, 
              ncp = NULL)
  </code></pre>
  
  <p>But it gives:</p>
  
  <pre><code>Error in interp.old(x, y, z, xo = xo, yo = yo, ncp = 0, extrap = extrap,  : 
  missing values and Infs not allowed
  </code></pre>
  
  <p>Let's check:
  <code>is.na(x), is.na(y), is.na(z)</code> all are FALSE</p>
  
  <pre><code>str(x)
  num [1:1398] 1.62 1.62 1.62 1.62 1.63 1.63 1.63 1.63 1.63 1.63 ...
  
  str(y)
  num [1:1398] 2993 2998 3001 3005 2993 ...
  
  str(z)
  'data.frame':   1398 obs. of  1 variable:
  $ V1: num  1 1 1 1 1 1 1 3 1 1 ...
  </code></pre>
  
  <p>What should I change?</p>