protected Vector3f getCenterLocation(TerrainPatch terrainPatch) {
        Vector3f loc = terrainPatch.getWorldTranslationCached();
        loc.x += terrainPatch.getSize()*terrainPatch.getWorldScaleCached().x / 2;
        loc.z += terrainPatch.getSize()*terrainPatch.getWorldScaleCached().z / 2;
        return loc;
    }
Calculates the LOD of the terrain based on its distance from the
cameras. Taking the minimum distance from all cameras.

@author bowens
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/lodcalc/DistanceLodCalculator.java