code: def txt_read_in(self):
          
  
          # read in
          data = ascii.read(self.WORKING_DIRECTORY + '/' + self.file_name)
  
          # find number of distinct x and y points.
          num_x_pts = len(np.unique(data[self.x_column_label]))
          num_y_pts = len(np.unique(data[self.y_column_label]))
  
          # create 2D arrays of x,y,z
          self.xvals = np.reshape(np.asarray(data[self.x_column_label]), (num_y_pts, num_x_pts))
          self.yvals = np.reshape(np.asarray(data[self.y_column_label]), (num_y_pts, num_x_pts))
          self.zvals = np.reshape(np.asarray(data[self.z_column_label]), (num_y_pts, num_x_pts))
  
          return
docs: Read in txt files.
  
          Method for reading in text or csv files. This uses ascii class from astropy.io
          for flexible input. It is slower than numpy, but has greater flexibility with less input.