diff --git a/src/engine/InterestManagement/HeightMap.java b/src/engine/InterestManagement/HeightMap.java
index 6527deb4..09d7b83c 100644
--- a/src/engine/InterestManagement/HeightMap.java
+++ b/src/engine/InterestManagement/HeightMap.java
@@ -262,11 +262,9 @@ public class HeightMap {
             percentage = currentDelta / blendDelta;
         else
             percentage = 0.0f;
-
-        interpolatedTerrainHeight = FastMath.LERP(percentage, interpolatedTerrainHeight, interpolatedParentTerrainHeight);
-
+        float interpolatedWorldAltitude = FastMath.LERP(percentage, heightMapZone.worldAltitude, parentZone.worldAltitude);
         interpolatedTerrainHeight = FastMath.LERP(percentage, interpolatedTerrainHeight, interpolatedParentTerrainHeight);
-        return interpolatedTerrainHeight + heightMapZone.worldAltitude;
+        return interpolatedTerrainHeight + interpolatedWorldAltitude;
 
     }