An integrated TIN and Grid method for constructing multi-resolution digital terrain models

Multi-resolution terrain models are an efficient approach to improve the speed of three-dimensional (3D) visualizations, especially for terrain visualization in Geographical Information Systems (GIS). As a further development to existing algorithms and models, a new model is proposed for the construction of multi-resolution terrain models in a 3D GIS. The new model represents multi-resolution terrains using two major methods for terrain representation: Triangulated Irregular Network (TIN) and regular grid (Grid). In this paper, first, the concepts and formal definitions of the new model are presented. Second, the methodology for constructing multi-resolution terrain models based on the new model is proposed. Third, the error of multi-resolution terrain models is analysed, and a set of rules is proposed to retain the important features (e.g. boundaries of man-made objects) within the multi-resolution terrain models. Finally, several experiments are undertaken to test the performance of the new model. The experimental results demonstrate that the new model can be applied to construct multi-resolution terrain models with good performance in terms of time cost and maintenance of the important features. Furthermore, a comparison with previous algorithms/models shows that the speed of rendering for 3D walking/flying through has been greatly improved by applying the new model.