small fix to avoid dask median NaN issues

Author: beatfactor

oceanstream/echodata/denoise/impulse_noise.py

@@ -172,6 +172,9 @@ def impulse_noise_mask(
             range_values = range_values.compute()
     elif range_values.dims:
         range_dim = range_values.dims[0]
+        # Materialise to avoid dask median NaN issues
+        if hasattr(range_values, "compute"):
+            range_values = range_values.compute()
     else:
         range_dim = range_coord
 
@@ -184,6 +187,8 @@ def impulse_noise_mask(
             window_m = float(s.rstrip("mM "))
             dz_arr = range_values.diff(range_dim)
             dz = float(dz_arr.median()) if dz_arr.size > 0 else 0.1
+            if np.isnan(dz) or dz == 0:
+                dz = 0.1
             bin_sz = max(1, int(round(window_m / abs(dz))))
         else:
             bin_sz = max(1, int(s))