diff --git a/src/mintpy/spatial_filter.py b/src/mintpy/spatial_filter.py
index 0507e67b0..f9a0e96a0 100644
--- a/src/mintpy/spatial_filter.py
+++ b/src/mintpy/spatial_filter.py
@@ -71,15 +71,17 @@ def filter_data(data, filter_type, filter_par=None):
         and regional mean results are separate.
         """
 
-        local_kernel = morphology.disk(filter_par[0], np.float32)
-        local_kernel = np.pad(local_kernel,filter_par[1] - filter_par[0],mode='constant')
+        local_kernel = morphology.disk(filter_par[0], dtype=np.float32)
+        local_kernel = np.pad(local_kernel, pad_width=int(filter_par[1]-filter_par[0]), mode='constant')
 
-        regional_kernel = morphology.disk(filter_par[1], np.float32)
+        regional_kernel = morphology.disk(filter_par[1], dtype=np.float32)
         regional_kernel[local_kernel == 1] = 0
 
+        # normalize
         local_kernel /= local_kernel.sum(axis=(0,1))
         regional_kernel /= regional_kernel.sum(axis=(0,1))
 
+        # double-difference kernel
         combined_kernel = regional_kernel - local_kernel
 
         data_filt = ndimage.convolve(data, combined_kernel)
@@ -107,7 +109,8 @@ def filter_file(fname, ds_names=None, filter_type='lowpass_gaussian', filter_par
     # Info
     filter_type = filter_type.lower()
     atr = readfile.read_attribute(fname)
-    msg = 'filtering {} file: {} using {} filter'.format(atr['FILE_TYPE'], fname, filter_type)
+    print(f'input file: {fname}, file type: {atr["FILE_TYPE"]}')
+    print(f'filter type: {filter_type}')
 
     if filter_type.endswith('avg'):
         if not filter_par:
@@ -115,7 +118,7 @@ def filter_file(fname, ds_names=None, filter_type='lowpass_gaussian', filter_par
         elif isinstance(filter_par, list):
             filter_par = filter_par[0]
         filter_par = int(filter_par)
-        msg += f' with kernel size of {filter_par}'
+        print(f'filter parameter: kernel size = {filter_par}')
 
     elif filter_type.endswith('gaussian'):
         if not filter_par:
@@ -123,14 +126,13 @@ def filter_file(fname, ds_names=None, filter_type='lowpass_gaussian', filter_par
         elif isinstance(filter_par, list):
             filter_par = filter_par[0]
         filter_par = float(filter_par)
-        msg += f' with sigma of {filter_par:.1f}'
+        print(f'filter parameter: sigma = {filter_par:.1f}')
 
     elif filter_type == 'double_difference':
         if not filter_par:
             filter_par = [1, 10]
         local, regional = int(filter_par[0]), int(filter_par[1])
-        msg += f' with local/regional kernel sizes of {local}/{regional}'
-    print(msg)
+        print(f'filter parameter: local / regional kernel sizes = {local} / {regional}')
 
     # output filename
     if not fname_out:
diff --git a/src/mintpy/utils/isce_utils.py b/src/mintpy/utils/isce_utils.py
index d37392434..7765213ea 100644
--- a/src/mintpy/utils/isce_utils.py
+++ b/src/mintpy/utils/isce_utils.py
@@ -385,10 +385,12 @@ def extract_alosStack_metadata(meta_file, geom_dir):
     meta['LON_REF3'] = str(data[-1-edge,  0+edge])
     meta['LON_REF4'] = str(data[-1-edge, -1-edge])
 
-    los_file = glob.glob(os.path.join(geom_dir, f'*_{rlooks}rlks_{alooks}alks.los'))[0]
-    data = np.memmap(los_file, dtype='float32', mode='r', shape=(length*2, width))[0:length*2:2, :]
-    inc_angle = data[int(length/2), int(width/2)]
-    meta['CENTER_INCIDENCE_ANGLE'] = str(inc_angle)
+    # CENTER_INCIDENCE_ANGLE is optional
+    los_files = glob.glob(os.path.join(geom_dir, f'*_{rlooks}rlks_{alooks}alks.los'))
+    if len(los_files) > 0:
+        data = np.memmap(los_files[0], dtype='float32', mode='r', shape=(length*2, width))[0:length*2:2, :]
+        inc_angle = data[int(length/2), int(width/2)]
+        meta['CENTER_INCIDENCE_ANGLE'] = str(inc_angle)
 
     pointingDirection = {'right': -1, 'left' :1}
     meta['ANTENNA_SIDE'] = str(pointingDirection[track.pointingDirection])
diff --git a/src/mintpy/utils/readfile.py b/src/mintpy/utils/readfile.py
index 4a4863ea8..182a6e1e7 100644
--- a/src/mintpy/utils/readfile.py
+++ b/src/mintpy/utils/readfile.py
@@ -1322,7 +1322,7 @@ def auto_no_data_value(meta):
 
         # known file types
         # isce2: dense offsets from topsApp.py
-        if processor == 'isce' and fbase.endswith('dense_offsets') and fext == '.bil' and num_band == 2:
+        if processor == 'isce' and fname.endswith('dense_offsets.bil') and num_band == 2:
             no_data_value = -10000.
 
         else:
diff --git a/src/mintpy/utils/writefile.py b/src/mintpy/utils/writefile.py
index 2575ece05..3384a84ba 100644
--- a/src/mintpy/utils/writefile.py
+++ b/src/mintpy/utils/writefile.py
@@ -171,7 +171,8 @@ def write(datasetDict, out_file, metadata=None, ref_file=None, compression=None,
                 data_list = [data_list[0], data_list[0]]
                 meta['BANDS'] = 2
 
-        elif fext in ['.cor', '.hgt']:
+        elif fext in ['.cor']:
+            # remove .hgt as it can be float64 in isce2.
             meta['DATA_TYPE'] = 'float32'
             meta['INTERLEAVE'] = 'BIL'
             if meta.get('PROCESSOR', 'isce') == 'roipac':