diff --git a/vtm/src/org/oscim/core/MapElement.java b/vtm/src/org/oscim/core/MapElement.java
index 0cbc8ef2..5fded8ef 100644
--- a/vtm/src/org/oscim/core/MapElement.java
+++ b/vtm/src/org/oscim/core/MapElement.java
@@ -66,7 +66,7 @@ public class MapElement extends GeometryBuffer {
      * @return height in meters, if present
      */
     public Float getHeight(IRenderTheme theme) {
-        String res = theme.transformKey(Tag.KEY_HEIGHT);
+        String res = theme != null ? theme.transformKey(Tag.KEY_HEIGHT) : Tag.KEY_HEIGHT;
         String v = tags.getValue(res != null ? res : Tag.KEY_HEIGHT);
         if (v != null)
             return Float.parseFloat(v);
@@ -77,7 +77,7 @@ public class MapElement extends GeometryBuffer {
      * @return minimum height in meters, if present
      */
     public Float getMinHeight(IRenderTheme theme) {
-        String res = theme.transformKey(Tag.KEY_MIN_HEIGHT);
+        String res = theme != null ? theme.transformKey(Tag.KEY_MIN_HEIGHT) : Tag.KEY_MIN_HEIGHT;
         String v = tags.getValue(res != null ? res : Tag.KEY_MIN_HEIGHT);
         if (v != null)
             return Float.parseFloat(v);
diff --git a/vtm/src/org/oscim/layers/tile/buildings/BuildingLayer.java b/vtm/src/org/oscim/layers/tile/buildings/BuildingLayer.java
index 985b1f10..cf4cb8ec 100644
--- a/vtm/src/org/oscim/layers/tile/buildings/BuildingLayer.java
+++ b/vtm/src/org/oscim/layers/tile/buildings/BuildingLayer.java
@@ -244,6 +244,8 @@ public class BuildingLayer extends Layer implements TileLoaderThemeHook, ZoomLim
     }
 
     protected String getKeyOrDefault(String key) {
+        if (mRenderTheme == null)
+            return key;
         String res = mRenderTheme.transformKey(key);
         return res != null ? res : key;
     }