title: Changing tick labels without affecting the plot
body: <p>I am plotting a 2-D array in python using matplotlib and am having trouble formatting the tick marks. So first, my data is currently organized as a 2-D array with (elevation, latitude). I am plotting values of electron density as a function of height and latitude (basically a longitudinal slice at a specific time).</p>
  
  <p>I want to label the x axis going from -90 to 90 degrees in 30 degree intervals and the y values with another array of elevations (each model run has different elevation values so I can't manually assign an arbitrary elevation). I have arrays with latitude values in it and another with elevation values both 1-D arrays. </p>
  
  <p>Here is my code:</p>
  
  <pre><code>from netCDF4 import Dataset
  import numpy as np
  import matplotlib.pyplot as plt
  
  #load the netcdf file into a variable
  mar120="C:/Users/WillEvo/Desktop/sec_giptie_cpl_mar_120.nc"
  
  #grab the data into a new variable
  fh=Dataset(mar120,mode="r")
  
  #assign model variable contents to python variables
  lons=fh.variables['lon'][:]
  lats=fh.variables['lat'][:]
  var1=fh.variables['UN'][:]
  
  #specifying which time and elevation to map
  ionst=var1[0,:,:,21]
  ionst=ionst[0:len(ionst)-1]
  
  #close the netCDF file
  fh.close()
  
  #Set the figure, size, and resolution
  plt.figure(figsize=(8,6), dpi=100, facecolor='white')
  plt.subplot(1,1,1)
  
  plt.imshow(ionst, origin='lower', interpolation='spline16')
  
  plt.xticks([-90, -60, -30, 0, 30, 60, 90])  
  plt.show()
  </code></pre>
  
  <p>If I don't include the plt.xticks argument I get the following good image but bad tick labels:</p>
  
  <p><img src="https://i.stack.imgur.com/ZbkK4.png" alt="Good Image but bad tick labeling"></p>
  
  <p>If I include the plt.xticks argument I get the following:</p>
  
  <p><img src="https://i.stack.imgur.com/0cckx.png" alt="Bad figure, data remains static"></p>
  
  <p>How can I fix this? I want the data to follow the change in axis (but be accurate). I also need to do this for the y axis but without manually entering values and instead feeding an array of values. Thanks</p>