3D terrain Overview

With the development of computer technology and related scientific theories, the production of three-dimensional electronic maps has gone through three stages: Line-drawn topographic maps, solid-type topographic maps, and three-dimensional realistic topographic maps.

3D terrain simulation is one of the most basic and important technologies in the development of visual systems. There are two types of terrain simulation: real terrain and simulated terrain.

Real terrain: real terrain is the reproduction of real terrain in the real world. It has a very high degree of authenticity and must be constructed using specific data in the real world, in this case, the digital elevation model (DEM) method is generally used. In this method, the data structure is complex, the number is very high, but the graphics generation speed is slow.

Simulated terrain: In the visualization process, the terrain generation is not very concerned, and the sensory requirements must be met. In this case, the simulated terrain can be used, generally, the terrain is generated randomly or fractal. The terrain generated using these methods is also very beautiful, and the graphics generation speed is also very fast, but it cannot match the real world one by one.

Implementation Method:

 

1. Real terrain

For the construction of real terrain, we usually use the longitude and latitude to form a normalized grid body forcing method. The main key technology is to obtain the relevant parameters of the grid points, including its longitude and latitude, elevation and color data.

 

2. Simulate terrain

(1) random terrain generation: The method for Generating Random elevation data is to randomly generate elevation data for some feature points, then, a relatively smooth terrain is generated by curve fitting between feature points, and colors are generated based on the elevation data on the grid or the external texture is directly attacked.

(2) fragment method: the generation method of fragment elevation data mainly uses the self-similarity principle of fragment.