diff --git a/etl/0_test_polygons.py b/etl/0_test_polygons.py
new file mode 100644
index 00000000..47c2c34e
--- /dev/null
+++ b/etl/0_test_polygons.py
@@ -0,0 +1,36 @@
+"""Download and load a small open dataset for testing
+"""
+import os
+import osmnx
+
+# configure logging/caching
+osmnx.config(log_console=True, use_cache=True)
+
+# configure the image display
+size = 256
+
+# load buildings from about 1.5km² around UCL
+point = (51.524498, -0.133874)
+dist = 612
+gdf = osmnx.buildings_from_point(point=point, distance=dist)
+
+# preview image
+gdf_proj = osmnx.project_gdf(gdf)
+bbox = osmnx.bbox_from_point(point=point, distance=dist, project_utm=True)
+fig, ax = osmnx.plot_buildings(gdf_proj, bgcolor='#333333', color='w', figsize=(4,4),
+                               bbox=bbox, save=True, show=False, close=True,
+                               filename='test_buildings_preview', dpi=90)
+
+# save as geojson
+test_data_file = os.path.join(os.path.dirname(__file__), 'test_buildings.geojson')
+
+gdf_to_save = gdf.reset_index(
+)[
+    ['index', 'geometry']
+]
+
+gdf_to_save.rename(
+    columns={'index': 'fid'}
+).to_file(
+    test_data_file, driver='GeoJSON'
+)