Fix future warning (#301)

* fixed future warning

* Specify minimum version for scikit-image 

Co-authored-by: Daniele Nerini <[email protected]>

Author: feldmann-m

doc/source/user_guide/install_pysteps.rst

@@ -37,7 +37,7 @@ Other optional dependencies include:
 * `pywavelets <https://pywavelets.readthedocs.io/en/latest/>`_
   (for intensity-scale verification)
 * `pandas <https://pandas.pydata.org/>`_ and
-  `scikit-image <https://scikit-image.org/>`_ (for advanced feature detection methods)
+  `scikit-image >=0.19 <https://scikit-image.org/>`_ (for advanced feature detection methods)
 * `rasterio <https://rasterio.readthedocs.io/en/latest/>`_ (for the reprojection module)
 
 

pysteps/feature/tstorm.py

@@ -150,7 +150,7 @@ def detection(
     if np.nanmax(filt_image.flatten()) < minref:
         maxima = np.zeros(filt_image.shape)
     else:
-        maxima = skim.h_maxima(filt_image, h=mindiff, selem=struct)
+        maxima = skim.h_maxima(filt_image, h=mindiff, footprint=struct)
     loc_max = np.where(maxima > 0)
 
     loc_max = longdistance(loc_max, mindis)