diff --git a/pygmtsar/pygmtsar/SBAS_geocode.py b/pygmtsar/pygmtsar/SBAS_geocode.py
index 9a02009f..7620944f 100644
--- a/pygmtsar/pygmtsar/SBAS_geocode.py
+++ b/pygmtsar/pygmtsar/SBAS_geocode.py
@@ -12,7 +12,7 @@
 
 class SBAS_geocode(SBAS_sbas):
 
-    def geocode_parallel(self, pairs=None, chunksize=None):
+    def geocode_parallel(self, pairs=None, coarsen=4, chunksize=None):
         """
         Perform parallel geocoding of the interferograms.
 
@@ -31,7 +31,7 @@ def geocode_parallel(self, pairs=None, chunksize=None):
         # build trans_dat, trans_ dat_inv and topo_ra grids for merged subswaths
         # for single-digit subswath the grids already created for interferogram processing
         if len(str(self.get_subswath())) > 1:
-            self.topo_ra_parallel()
+            self.topo_ra_parallel(coarsen=coarsen)
 
         # build geographic coordinates transformation matrix for landmask and other grids
         self.intf_ll2ra_matrix_parallel(pairs=pairs, chunksize=chunksize)
diff --git a/pygmtsar/pygmtsar/SBAS_topo_ra.py b/pygmtsar/pygmtsar/SBAS_topo_ra.py
index b423bf5e..22658178 100644
--- a/pygmtsar/pygmtsar/SBAS_topo_ra.py
+++ b/pygmtsar/pygmtsar/SBAS_topo_ra.py
@@ -100,7 +100,7 @@ def topo_ra_parallel(self, coarsen=4, interactive=False, **kwargs):
         # cleanup - sometimes writing NetCDF handlers are not closed immediately and block reading access
         import gc; gc.collect()
 
-    def get_topo_ra(self):
+    def get_topo_ra(self, chunksize=None):
         """
         Get the radar topography grid.
 
@@ -123,6 +123,9 @@ def get_topo_ra(self):
         import xarray as xr
         import dask.array
 
+        if chunksize is None:
+            chunksize = self.chunksize
+
         def func(topo):
             # flip vertically for GMTSAR compatibility reasons
             topo = xr.DataArray(dask.array.flipud(topo), coords=topo.coords, attrs=topo.attrs, name=topo.name)
@@ -131,6 +134,6 @@ def func(topo):
                 return topo.rename({'a': 'y', 'r': 'x'})
             return topo
 
-        topos = self.open_grids(None, 'topo_ra', func=func)
+        topos = self.open_grids(None, 'topo_ra', chunksize=chunksize, func=func)
 
         return topos[0] if len(topos)==1 else topos