diff --git a/src/c3nav/mapdata/render/base.py b/src/c3nav/mapdata/render/base.py
index a5c021e0..7d12b63c 100644
--- a/src/c3nav/mapdata/render/base.py
+++ b/src/c3nav/mapdata/render/base.py
@@ -58,7 +58,8 @@ def get_render_level_data(level):
         level_pk, level_base_altitude = Level.objects.filter(pk=level).values_list('pk', 'base_altitude')[0]
 
     levels = Level.objects.filter(Q(on_top_of=level_pk) | Q(base_altitude__lte=level_base_altitude))
-    result = levels.values_list('geoms_cache', 'default_height')
+    result = ((pickle.loads(geoms_cache), default_height)
+              for geoms_cache, default_height in levels.values_list('geoms_cache', 'default_height'))
     cache.set(cache_key, result, 900)
 
     return levels
diff --git a/src/c3nav/mapdata/render/svg.py b/src/c3nav/mapdata/render/svg.py
index ce55eca8..6018f541 100644
--- a/src/c3nav/mapdata/render/svg.py
+++ b/src/c3nav/mapdata/render/svg.py
@@ -1,5 +1,3 @@
-import pickle
-
 from shapely.geometry import box
 
 from c3nav.mapdata.render.base import get_render_level_data
@@ -12,8 +10,7 @@ def render_svg(level, miny, minx, maxy, maxx, scale=1):
     within_coords = (minx-2, miny-2, maxx+2, maxy+2)
     bbox = box(*within_coords)
 
-    for geoms_cache, default_height in get_render_level_data(level):
-        geoms = pickle.loads(geoms_cache)
+    for geoms, default_height in get_render_level_data(level):
         for altitudearea_geom, altitude in geoms.altitudeareas:
             svg.add_geometry(bbox.intersection(altitudearea_geom), fill_color='#eeeeee', altitude=altitude)