center(extent) {
        extent.center(this.tmp.coords);
        center.set(this.tmp.coords.x, this.tmp.coords.y, 0);
        return center;
    }
// get center tile in cartesian 3D
get center tile in cartesian 3D
get center tile in cartesian 3D
center(extent) {
        extent.center(this.tmp.coords);
        center.set(this.tmp.coords.x, this.tmp.coords.y, 0);
        return center;
    }
center ( extent ) { extent . center ( this . tmp . coords ) ; center . set ( this . tmp . coords . x , this . tmp . coords . y , 0 ) ; return center ; }
get center tile in cartesian 3D
get center tile in cartesian 3D