title: How to fix "not enough values to unpack (expected 2, got 1)"?
body: <p>I have zero background in programming. I am trying to code something for my class and it is giving me an error "not enough values to unpack (expected 2, got 1)". What might be wrong with my codes?</p>
  
  <pre><code>from mpl_toolkits.basemap import Basemap
  import matplotlib.pyplot as plt
  import pandas as pd
  import numpy as np
  import shapefile as shp
  
  #Read x, y, z file
  data = pd.read_excel('RegionV.xlsx', header = None)
  
  # Get X, Y, Z values from file
  data = np.array(data)
  data = data.astype(np.float)
  x = data[:,0]
  y =  data[:,1]
  z = data[:,2]
  
  #Mask negative values of z (bathemetry)
  zz = np.ma.masked_where(z &lt;= 0, z)
  
  
  #Create a map using basemap
  fig = plt.figure(figsize=(10,10))
  map = Basemap(projection='mill',llcrnrlat=11,urcrnrlat=15,\
              llcrnrlon=122,urcrnrlon=125,resolution='h')
  
  lon = np.linspace(min(x), max(x))
  lat = np.linspace(min(y), max(y))
  
  xs, ys = np.meshgrid(lon, lat)
  x, y = map(xs, ys)
  
  
  map.drawparallels(np.arange(12.,14.,0.5), labels=[0,0,0,1])
  map.drawmeridians(np.arange(123.,126.,0.5), labels=[1,0,0,0])
  
  #Plot 
  cmap = plt.cm.jet
  cmap.set_bad(color='white')
  m.pcolormesh(x, y, zz, cmap=cmap, vmax=1300, vmin=0) 
  m.colorbar(location='right', label='meters')
  
  
  map.drawmapboundary()
  map.drawcoastlines()
  </code></pre>
  
  <p>the first part of the error message says:</p>
  
  <pre><code>ValueError                                Traceback (most recent call last)
      &lt;ipython-input-50-3d7531011dc2&gt; in &lt;module&gt;
           44 cmap = plt.cm.jet
           45 cmap.set_bad(color='white')
      ---&gt; 46 m.pcolormesh(xs, ys, zz, cmap=cmap, vmax=1300, vmin=0)
           47 m.colorbar(location='right', label='meters')
  </code></pre>
  
  <p>then, at the end, </p>
  
  <pre><code>ValueError: not enough values to unpack (expected 2, got 1)
  </code></pre>
  
  <p>Stackoverflow is not allowing me to post the entire error message. Hope everyone who see my post understands what I mean. </p>