diff --git a/ecml_tools/data.py b/ecml_tools/data.py
index ba4f1e1..737b10b 100644
--- a/ecml_tools/data.py
+++ b/ecml_tools/data.py
@@ -119,6 +119,7 @@ def __init__(self, path):
             self.z = path
         else:
             self.path = path
+            print(path)
             self.z = zarr.convenience.open(path, "r")
 
     def __len__(self):
@@ -137,11 +138,19 @@ def dates(self):
 
     @property
     def latitudes(self):
-        return self.z.latitudes[:]
+        try:
+            return self.z.latitudes[:]
+        except AttributeError:
+            LOG.warning("No 'latitudes' in %r, trying 'latitude'", self)
+            return self.z.latitude[:]
 
     @property
     def longitudes(self):
-        return self.z.longitudes[:]
+        try:
+            return self.z.longitudes[:]
+        except AttributeError:
+            LOG.warning("No 'longitudes' in %r, trying 'longitude'", self)
+            return self.z.longitude[:]
 
     @property
     def statistics(self):
@@ -153,7 +162,13 @@ def resolution(self):
 
     @property
     def frequency(self):
-        return self.z.attrs["frequency"]
+        try:
+            return self.z.attrs["frequency"]
+        except KeyError:
+            LOG.warning("No 'frequency' in %r, computing from 'dates'", self)
+        dates = self.dates
+        delta = dates[1].astype(object) - dates[0].astype(object)
+        return delta.total_seconds() // 3600
 
     @property
     def name_to_index(self):
diff --git a/test.py b/test.py
index 55254f3..da4d496 100644
--- a/test.py
+++ b/test.py
@@ -1,6 +1,6 @@
 from ecml_tools.data import open_dataset
 
-name = "aifs-od-an-oper-0001-mars-o96-2021-6h-v2"
+name = "aifs-ea-an-oper-0001-mars-o96-2021-6h-v2-only-z"
 # aifs-od-an-oper-0001-mars-o96-2021-6h-v2"
 z = open_dataset(name)