[snap.geocode] raise RuntimeError if the sensor is not S1A or S1B

The recent workflow modifications require reading the image geometry
from the source product. Reading this attribute is currently only
supported for Sentinel-1 via the drivers.SAFE class

pyroSAR/snap/util.py

@@ -199,6 +199,9 @@ def geocode(infile, outdir, t_srs=4326, tr=20, polarizations='all', shapefile=No
 
     ############################################
     # Multilook node configuration
+    if id.sensor not in ['S1A', 'S1B']:
+        raise RuntimeError('This function is currently limited to Sentinel-1')
+
     ml_az = int(math.floor(tr / id.spacing[1]))
     if id.meta['image_geometry'] == 'Ground Range':
         ml_rg = ml_az
@@ -207,9 +210,6 @@ def geocode(infile, outdir, t_srs=4326, tr=20, polarizations='all', shapefile=No
         ml_rg = int(math.floor(tr / spacing_gr))
 
     if ml_az > 1 or ml_rg > 1:
-        if id.sensor not in ['S1A', 'S1B']:
-            raise RuntimeError('This workflow requires multilooking, '
-                               'which is currently only supported for Sentinel-1')
         insert_node(workflow, parse_node('Multilook'), after=tf.attrib['id'])
         ml = workflow.find('.//node[@id="Multilook"]')
         ml.find('.//parameters/sourceBands').text = bands_beta