diff --git a/SimPEG/PropMaps.py b/SimPEG/PropMaps.py
index d7bd2ba2..995216f7 100644
--- a/SimPEG/PropMaps.py
+++ b/SimPEG/PropMaps.py
@@ -1,4 +1,4 @@
-import Utils, Maps, numpy as np
+import Utils, Maps, numpy as np, scipy.sparse as sp
 
 class Property(object):
 
@@ -87,10 +87,23 @@ class Property(object):
             mapping = getattr(self, '%sMap'%prop.name)
             if mapping is None:
                 return None
-            index = getattr(self.propMap, '_%sIndex'%prop.name, slice(None))
+            index = getattr(self.propMap, '%sIndex'%prop.name)
             return self.vector[index]
         return property(fget=fget)
 
+    def _getModelProjProperty(self):
+        prop = self
+        def fget(self):
+            mapping = getattr(self, '%sMap'%prop.name)
+            if mapping is None:
+                return None
+            inds = getattr(self.propMap, '%sIndex'%prop.name)
+            if type(inds) is slice:
+                inds = range(*inds.indices(self.nP))
+            nI, nP = len(inds),self.nP
+            return sp.csr_matrix((np.ones(nI), (range(nI), inds) ), shape=(nI, nP))
+        return property(fget=fget)
+
     def _getModelMapProperty(self):
         prop = self
         def fget(self):
@@ -119,6 +132,9 @@ class PropModel(object):
             self._nP = len(set(inds))
         return self._nP
 
+    def __contains__(self, val):
+        return val in self.propMap
+
 
 
 _PROPMAPCLASSREGISTRY = {}
@@ -167,6 +183,7 @@ class _PropMapMetaClass(type):
 
             attrs[attr          ] = prop._getProperty()
             attrs[attr + 'Map'  ] = prop._getModelMapProperty()
+            attrs[attr + 'Proj' ] = prop._getModelProjProperty()
             attrs[attr + 'Model'] = prop._getModelProperty()
             attrs[attr + 'Deriv'] = prop._getModelDerivProperty()
 
@@ -238,3 +255,6 @@ class PropMap(object):
     def __call__(self, vec):
         return self.PropModel(self, vec)
 
+    def __contains__(self, val):
+        activeMaps = [name for name in self._properties if getattr(self, '%sMap'%name) is not None]
+        return val in activeMaps
diff --git a/SimPEG/Tests/test_PropMaps.py b/SimPEG/Tests/test_PropMaps.py
index c2726d71..b4c0eb8d 100644
--- a/SimPEG/Tests/test_PropMaps.py
+++ b/SimPEG/Tests/test_PropMaps.py
@@ -36,7 +36,16 @@ class TestPropMaps(unittest.TestCase):
             assert PM.muMap is None
             assert PM.muIndex is None
 
+            assert 'sigma' in PM
+            assert 'mu' not in PM
+            assert 'mui' not in PM
+
             m = PM(np.r_[1.,2,3])
+
+            assert 'sigma' in m
+            assert 'mu' not in m
+            assert 'mui' not in m
+
             assert m.mu == mu_0
             assert m.muModel is None
             assert m.muMap is None
@@ -67,6 +76,14 @@ class TestPropMaps(unittest.TestCase):
 
         assert pm.nP == 6
 
+        assert 'sigma' in PM
+        assert 'mu' in PM
+        assert 'mui' not in PM
+
+        assert 'sigma' in pm
+        assert 'mu' in pm
+        assert 'mui' not in pm
+
         assert np.all(pm.sigmaModel == [1.,2,3])
         assert np.all(pm.sigma == np.exp([1.,2,3]))
         assert np.all(pm.muModel == [4.,5,6])
@@ -83,11 +100,33 @@ class TestPropMaps(unittest.TestCase):
 
         assert pm.nP == 3
 
+        assert 'sigma' in PM
+        assert 'mu' in PM
+        assert 'mui' not in PM
+
+        assert 'sigma' in pm
+        assert 'mu' in pm
+        assert 'mui' not in pm
+
         assert np.all(pm.sigmaModel == [1,2,3])
         assert np.all(pm.sigma == np.exp([1,2,3]))
         assert np.all(pm.muModel == [1,2,3])
         assert np.all(pm.mu == [1,2,3])
 
+    def test_Projections(self):
+        m = Mesh.TensorMesh((3,))
+        iMap = Maps.IdentityMap(m)
+        PM = MyReciprocalPropMap([('sigma', iMap)])
+        v = np.r_[1,2.,3]
+        pm = PM(v)
+
+        assert pm.sigmaProj is not None
+        assert pm.rhoProj   is None
+        assert pm.muProj    is None
+        assert pm.muiProj   is None
+
+        assert np.all(pm.sigmaProj * v == pm.sigmaModel)
+
     def test_Links(self):
         m = Mesh.TensorMesh((3,))
         expMap = Maps.ExpMap(m)
@@ -103,6 +142,17 @@ class TestPropMaps(unittest.TestCase):
         assert pm.sigmaDeriv is not None
         assert pm.rhoDeriv is not None
 
+        assert 'sigma' in PM
+        assert 'rho' not in PM
+        assert 'mu' not in PM
+        assert 'mui' not in PM
+
+
+        assert 'sigma' in pm
+        assert 'rho' not in pm
+        assert 'mu' not in pm
+        assert 'mui' not in pm
+
         assert pm.mu == mu_0
         assert pm.mui == 1.0/mu_0
         assert pm.muMap is None
@@ -121,6 +171,17 @@ class TestPropMaps(unittest.TestCase):
         assert pm.sigmaDeriv is not None
         assert pm.rhoDeriv is not None
 
+        assert 'sigma' not in PM
+        assert 'rho' in PM
+        assert 'mu' not in PM
+        assert 'mui' not in PM
+
+
+        assert 'sigma' not in pm
+        assert 'rho' in pm
+        assert 'mu' not in pm
+        assert 'mui' not in pm
+
         self.assertRaises(AssertionError, MyReciprocalPropMap, [('rho', iMap), ('sigma', iMap)])
         self.assertRaises(AssertionError, MyReciprocalPropMap, [('sigma', iMap), ('rho', iMap)])