In addition, the theories and methods used in the space field could be applied to help people observe and analyze abstract data. and people's visual and image thinking can play a role. In virtual terrains, the original abstract data can obtain specific positions, shapes, colors, etc. For instance, some virtual terrains can be built based on computer technologies and visualization methods. There are also many studies that use spatial metaphors to express non-location data in the field of visualization. Among the various types, spatial metaphors are relatively common because of their intuitive and sensible nature. Metaphor are commonly used rhetorical devices in linguistics. Such a technique should also be used on low/medium end PCs, and embedded systems that are not equipped with the latest models of graphic hardware. The experimental results demonstrate that the proposed approach drastically reduces computation time in the CPU. Tests and experiments demonstrate that B-spline 0 and B-spline 1 wavelets, well known for their properties of localization and their compact support, are suitable for fast and accurate localization of the maximum approximation error. Maximum world-space errors of the tile at different resolutions permit selection of the appropriate resolution of downsampling that will represent the tile at the run time. Maximum approximation errors are then calculated for each tile at different resolutions. The training stage is based on multiresolution wavelet decomposition and is used to limit the region of error control inside the tile.

As the datasets of realistic terrains are usually huge for real-time rendering, we suggest using a training stage to handle large tiled QuadTree terrain representation. The proposed approach alleviates the computational load on the CPU and approaches GPU-based efficiency. This paper describes a central processing unit (CPU)-based technique for terrain geometry rendering that could relieve graphics processing unit (GPU) from processing the appropriate level of detail (LOD) of the geometric surface.

Tessellation graphics