Second Type Error fixed

Author: emason

README.md

@@ -5,4 +5,4 @@
 To avoid problem with installation, maybe prefer virtual environnement.
 
 * ** pip install cython **
-* ** python setup.py install**
+* ** python setup.py install**

src/py_eddy_tracker/property_objects.py

@@ -87,7 +87,7 @@ def __init__(self, contlon, contlat, eddy, grd):
         self.amplitude = 0  # atleast_1d(0.)
         self.local_extrema = None  # int(0)
         self.local_extrema_inds = None
-        self.sla = ma.array(self.sla, mask=-self.mask)
+        self.sla = ma.array(self.sla, mask=~self.mask)
 
     @property
     def islice(self):