title: plot gebco data in python basemap
body: <p>I have downloaded some gebco bathymetry data as a netCDF file. I would like to plot it with python-basemap. I have tried,</p>
  
  <pre><code>import netCDF4
  from mpl_toolkits.basemap import Basemap
  
  
  # Load data
  dataset = netCDF4.Dataset('/home/david/Desktop/GEBCO/gebco_08_-30_45_5_65.nc')
  
  # Extract variables
  x = dataset.variables['x_range']
  y = dataset.variables['y_range']
  spacing = dataset.variables['spacing']
  
  # Data limits
  nx = (x[-1]-x[0])/spacing[0]   # num pts in x-dir
  ny = (y[-1]-y[0])/spacing[1]   # num pts in y-dir
  
  # Reshape data
  zz = dataset.variables['z']
  Z = zz[:].reshape(ny, nx)
  
  
  
  # setup basemap.
  m = Basemap(llcrnrlon=-30,llcrnrlat=45.0,urcrnrlon=5.0,urcrnrlat=65.0,
              resolution='i',projection='stere',lon_0=-15.0,lat_0=55.0)
  
  
  # Set up grid
  lons, lats = m.makegrid(nx, ny)
  x, y = m(lons, lats)
  
  m.contourf(x, y, flipud(Z))
  m.fillcontinents(color='grey')
  m.drawparallels(np.arange(10,70,10), labels=[1,0,0,0])
  m.drawmeridians(np.arange(-80, 5, 10), labels=[0,0,0,1])
  </code></pre>
  
  <p>this gives the figure below, clearly not correct. The problem stems from how the areas are defined. For basemap area is defined by lower left corner lat,lon and upper right corner lat, lon. But the gebco data takes a maximum and minimum lon/lat defined along a center line.
  Anyone have any experience with gebco data or see a solution??</p>
  
  <p>thanks
  D
  <img src="https://i.stack.imgur.com/DSg1x.png" alt="map"></p>