diff --git a/pypret/mesh_data.py b/pypret/mesh_data.py
index 71efdd7..61530d2 100644
--- a/pypret/mesh_data.py
+++ b/pypret/mesh_data.py
@@ -161,6 +161,8 @@ def interpolate(self, axis1=None, axis2=None, degree=2, sorted=False):
                     uncertainty = np.take(uncertainty, idx, axis=i)
         dataf = RegularGridInterpolator(tuple(orig_axes), data,
                                         bounds_error=False, fill_value=0.0)
+        # Resample the axes to be evenly spaced
+        axes = [np.linspace(axis[0],axis[-1],len(axis),endpoint=True) for axis in axes]
         grid = lib.build_coords(*axes)
         self.data = dataf(grid)
         self.axes = axes
diff --git a/pypret/retrieval/retriever.py b/pypret/retrieval/retriever.py
index 701e975..d486804 100644
--- a/pypret/retrieval/retriever.py
+++ b/pypret/retrieval/retriever.py
@@ -7,6 +7,7 @@
 from ..pulse_error import pulse_error
 from .. import lib
 from ..pnps import BasePNPS
+from math import isclose
 
 # global dictionary that contains all PNPS classes
 _RETRIEVER_CLASSES = {}
@@ -106,7 +107,7 @@ def retrieve(self, measurement, initial_guess, weights=None,
 
     def _retrieve_begin(self, measurement, initial_guess, weights):
         pnps = self.pnps
-        if not np.all(pnps.process_w == measurement.axes[1]):
+        if not np.allclose(pnps.process_w, measurement.axes[1], rtol=1e-6):
             raise ValueError("Measurement has to lie on simulation grid!")
         # Store measurement
         self.measurement = measurement