text: """
  Cell 1 Features
  ====================================
  
  Compute features for 1-cells
  """
  # sphinx_gallery_thumbnail_number = 1
  
  from __future__ import print_function, division
  
  import nifty.cgp as ncgp
  import nifty.segmentation as nseg
  
  import skimage.data    as sdata
  import skimage.filters as sfilt
  
  # plotting
  import pylab
  
  
  # get data
  img = sdata.coins()
  
  # edge indicator
  edgeIndicator = sfilt.prewitt(sfilt.gaussian(img, 3))
  
  # watersheds
  overseg = nseg.seededWatersheds(edgeIndicator, 
          method='node_weighted', acc='min')
  
  f = pylab.figure()
  f.add_subplot(2,2,1)
  pylab.imshow(img/255)
  f.add_subplot(2,2,2)
  pylab.imshow(edgeIndicator)
  f.add_subplot(2,2,3)
  pylab.imshow(overseg, cmap=nseg.randomColormap(overseg.max()+1))
  f.add_subplot(2,2,4)
  pylab.imshow(nseg.markBoundaries(img, overseg))
  pylab.show()
  
  
  # cgp
  assert overseg.min() == 1
  tgrid = ncgp.TopologicalGrid2D(overseg)
  geometry = tgrid.extractCellsGeometry()
  bounds = tgrid.extractCellsBounds()
  boundedBy = {1:bounds[0].reverseMapping(), 
               2:bounds[1].reverseMapping()}
  
  
  # compute features
  cell1Features, cell1FeatureNames = ncgp.cell1Features(tgrid=tgrid, geometry=geometry,
      bounds=bounds, boundedBy=boundedBy)
  
  
  print(cell1Features.shape)