code: def s_grid_2d_dx(dx, sources, targets):
      dxa = np.abs(dx)
      sources = sources[dxa <= 1]
      targets = targets[dxa <= 1]
      return sources, targets
  
file_path: deepgraph/doc/source/tutorials/precipitation.py
imports: import os
  import xarray
  import matplotlib.pyplot
  import numpy
  import pandas
  import deepgraph
  from mpl_toolkits.basemap import Basemap
  from scipy.cluster.hierarchy import linkage, fcluster
label_desc: Use image node_id 3 for calling a global function with example usage: s_grid_2d_dx(dx, sources, targets) and returns: sources,  targets