What is virtual reality? What is its significance and development prospect in GIS visualization

Geological phenomena are inseparable from the essential laws of geology, and geoscience visualization, as a branch of scientific computing visualization in geoscience, has always been an important part of geo-information science with the core task of simulating, abstracting and reproducing various geoscientific phenomena. The visualization system is an important part of the GIS system, reflecting the ability of the GIS system to express spatial information, and is also an important indicator of the GIS system.

GIS two-dimensional visualization along the means of traditional cartography, through a variety of thematic maps, symbol libraries and other cartographic abstract symbols to express geographic information, geographic information to provide a macro-abstract expression, greatly simplifying the use of maps, query and analysis. But the two-dimensional GIS provides users with only two-dimensional plane graphics, in the degree of visualization than the traditional paper maps and no substantial improvement, with the GIS application continues to deepen, which is far from being able to meet people's visual requirements. The world was originally in three-dimensional space, two-dimensional visualization of the real world is simplified as a two-dimensional projection on the plane of the conceptual model is destined to be in the description of the limitations of three-dimensional spatial phenomena, to solve this problem is an effective means of three-dimensional GIS visualization. Computer graphics and a variety of graphics hardware technology continues to develop and people's visual requirements continue to improve, but also for the development of three-dimensional GIS visualization provides the impetus to create the conditions.

At present, some GIS vendors have developed and provided three-dimensional visualization system, but these systems due to various reasons have not been able to do downward compatibility, two-dimensional system and three-dimensional system is completely cut off, not only the data can not be directly **** to enjoy, and the complexity of the three-dimensional scene production process.

The ideal visualization method should be based on meeting people's visualization needs and providing high-performance 3D visualization functions, but also be fully compatible with 2D visualization expressions, improving reuse capabilities and reducing development and production costs, including:

1) compatibility with existing 2D GIS data;

2) compatibility with existing 2D thematic map

3) Compatible with the existing 2D symbol library system;

4) Compatible with the existing 2D GIS interaction.

The integration of 2D and 3D can make full and effective use of rich 2D spatial data resources, and at the same time can meet the needs of 3D modeling and visualization, realize the smooth transition from 2D to 3D GIS, and combine with dynamic GIS to realize multi-dimensional dynamic GIS.

At present, some international and domestic visionary GIS enterprises have begun to research on the integration of two-dimensional and three-dimensional technology, and the commercialized GIS of 2D and 3D integration has been developed. The integration of two-dimensional and three-dimensional commercial GIS software is expected to be launched in the middle of the "Eleventh Five-Year Plan".