Though considerable progress has been made with the view-dependent techniques in terrain visualization, the CPU overhead still precludes their wide application in many domains. The calculation complexity of viewdependent techniques mainly involves the calculation of node screen space error every frame, including the time-consuming screen space projection, the number of nodes whose projection error remains to be updated, and the evaluation of the valid life of the projection error. In this paper we introduce block-priority-based traversal of quadtree for reducing the traversal complexity and propose view-angle-based error metrics. Thus we successfully speed up the valid life evaluation of projection error by means of calculating the spatial relation between the viewpoint and a simplified split zone. In addition, constant frame rate has been achieved by scaling the split zone accordingly. Corresponding experimental results have shown that our methods can real-time render large scale ter...