geographical information system (GIS)

Geographic Information System (GIS) appeared in 1960s. As a powerful tool for experts in the field of geosciences, it has attracted more and more attention and been applied in many fields.

GIS is a computer system that collects, stores, retrieves, analyzes, models and represents geospatial data. It can not only manage digital and literal (attribute) information, but also manage spatial information (graphics), and provide various spatial analysis methods to comprehensively analyze and explain various spatial information, solve the relationship between spatial entities, and analyze various phenomena and processes occurring in a certain geographical area. GIS provides geologists with a powerful tool to comprehensively analyze and interpret multi-source information such as geology, geography, geophysics, geochemistry and remote sensing with the help of computers. Because GIS has interactive processing ability and fast calculation ability, geologists can easily improve their knowledge model through repeated attempts.

According to the purpose of research and development, GIS can be divided into national basic geographic information system, urban geographic information system and enterprise geographic information system. According to its research and development scope, it can be divided into global, regional and local geographic information systems; According to its space-time model, it can be divided into two-dimensional (location model), three-dimensional (location model+digital elevation model) and four-dimensional (three-dimensional+time model) geographic information systems or dynamic geographic information systems.

Besides software and hardware, data is the key of geographic information system. The main means for GIS to obtain data are GPS (Global Positioning System), DTS (Digital Total Station), DPS (Digital Photogrammetry System) and RS (Remote Sensing Technology).

In the mid-1980s, GIS began to be applied to earth science. The US Geological Survey established a GIS laboratory in 1985 to encourage professionals to apply new technologies. In just a few years, there are dozens of information management projects such as basic geology, environment and disasters, mineral resources evaluation and regional geological survey.

The application prospect of GIS in geoscience is very broad. After the information is analyzed and processed by GIS, topographic maps of Gobi, desert, plateau, snow-capped mountains and other areas that are difficult to reach by conventional surveying and mapping can be drawn. At present, the application of GIS in geoscience mainly includes:

(1) Geological prospecting and mineral resources prediction and evaluation

The SPOT satellite launched by Germany is mainly used for the investigation of oil, natural gas and other minerals. It can observe the terrain stereoscopically and produce high-resolution and high-precision images. Using this image, we can accurately and quickly find out the topography, surface outcrop, lithologic combination and the basic form of underground structure in the early stage of exploration.

(2) Land and resources management

1990, China established 1: 1 10,000 land and resources information system,1:40,000 national natural resources comprehensive development decision-making information system and some provinces, cities and counties land planning management information systems for national and regional economic construction and planning.

(3) Assessment and prevention of natural disasters

In China, 1990 established a flood forecasting system. 199 1 200,000 GIS information system and1200,000 Taihu Lake GIS land planning information database combined with remote sensing images respectively monitored the floods in Jianghuai area and Minjiang River and Pearl River basins in China in 1994, which made an accurate assessment of the disaster situation and reduced the flood losses. Japan's application of geographic information system analysis 1995 Osaka Kobe earthquake caused by landslides is also a prominent example.

In terms of seismic fortification zoning and disaster prevention planning, the disaster prevention planning compiled by GIS has the characteristics of convenient application, strong data practicability and resource sharing.

(4) Establish geoscience information base and compile geoscience map.

At present, many countries, such as the United States, German, French, Canadian and China, have used GIS to do this work.