diff --git a/src/sweets/_missing_data.py b/src/sweets/_missing_data.py
index 7083f12..11e667b 100644
--- a/src/sweets/_missing_data.py
+++ b/src/sweets/_missing_data.py
@@ -25,7 +25,10 @@
 
 
 def get_geodataframe(
-    gslc_files: Iterable[Filename], max_workers: int = 5, one_per_burst: bool = True
+    gslc_files: Iterable[Filename],
+    max_workers: int = 5,
+    one_per_burst: bool = True,
+    polygons: Optional[Sequence[geometry.Polygon]] = None,
 ) -> gpd.GeoDataFrame:
     """Get a GeoDataFrame of the CSLC footprints.
 
@@ -37,24 +40,29 @@ def get_geodataframe(
         Number of threads to use.
     one_per_burst : bool, default=True
         If True, only keep one footprint per burst ID.
+    polygons : Sequence[shapely.geometry.Polygon], optional
+        If provided, skips computing them from the CSLCs.
+        Otherwise, will read them in with `get_cslc_polygon`.
     """
     gslc_files = list(gslc_files)  # make sure generator doesn't deplete after first run
-    if one_per_burst:
-        from opera_utils import group_by_burst
-
-        burst_to_file_list = group_by_burst(gslc_files)
-        slc_files = [file_list[0] for file_list in burst_to_file_list.values()]
-        unique_polygons = thread_map(
-            get_cslc_polygon, slc_files, max_workers=max_workers
-        )
-        assert len(unique_polygons) == len(burst_to_file_list)
-        # Repeat the polygons for each burst
-        polygons: list[geometry.Polygon] = []
-        for burst_id, p in zip(burst_to_file_list, unique_polygons):
-            for _ in range(len(burst_to_file_list[burst_id])):
-                polygons.append(p)
-    else:
-        polygons = thread_map(get_cslc_polygon, gslc_files, max_workers=max_workers)
+    if not polygons:
+        polys: list[geometry.Polygon] = []
+        if one_per_burst:
+            from opera_utils import group_by_burst
+
+            burst_to_file_list = group_by_burst(gslc_files)
+            slc_files = [file_list[0] for file_list in burst_to_file_list.values()]
+            unique_polygons = thread_map(
+                get_cslc_polygon, slc_files, max_workers=max_workers
+            )
+            assert len(unique_polygons) == len(burst_to_file_list)
+            # Repeat the polys for each burst
+            for burst_id, p in zip(burst_to_file_list, unique_polygons):
+                for _ in range(len(burst_to_file_list[burst_id])):
+                    polys.append(p)
+        else:
+            polys = thread_map(get_cslc_polygon, gslc_files, max_workers=max_workers)
+        polygons = polys
 
     gdf = gpd.GeoDataFrame(geometry=polygons, crs="EPSG:4326")
     gdf["count"] = 1