diff --git a/src/c3nav/mapdata/render/renderer.py b/src/c3nav/mapdata/render/renderer.py
index 7a92dc9e..16e6d0b6 100644
--- a/src/c3nav/mapdata/render/renderer.py
+++ b/src/c3nav/mapdata/render/renderer.py
@@ -98,7 +98,7 @@ class MapRenderer:
                         j += 1
                         hexcolor = ''.join(hex(int(i*255))[2:].zfill(2) for i in engine.color_to_rgb(color)).upper()
                         engine.add_geometry(hybrid_union(areas), fill=FillAttribs(color),
-                                            category='groundcolor_%s' % hexcolor, item=j)
+                                            category='ground_%s' % hexcolor, item=j)
 
                 for height, obstacle in altitudearea.obstacles.items():
                     engine.add_geometry(obstacle, fill=FillAttribs('#cccccc'), category='obstacles')