3s and its application in the field of land resource management. What are the characteristics and advantages of these technologies?

3S is the general name of remote sensing technology RS, geographic information technology GIS and global positioning technology GPS. The "3S" technology is widely used in water conservancy industry, such as water resources investigation, ecological environment management, drought monitoring, irrigation area monitoring and planning, water environment evaluation, flood control and disaster reduction, soil and water conservation, dynamic monitoring of river evolution in estuaries and rivers, site selection of water conservancy projects, dynamic monitoring of reservoir capacity and lakes, and reservoir resettlement. With the rapid development of computer technology, the application of "3S" in water conservancy field is more and more extensive and in-depth. The future development direction is bound to be a 3S integrated system with mass data storage function, network function, geographic information modeling function and wireless communication function.

I. Overview:

Remote Sensing Technology refers to the use of optics or electro-optics (called remote sensors or wave detection instruments) to receive electromagnetic wave signals reflected or received from the ground in remote altitude and outer space, record them in the form of image film or data tape, transmit them to the ground, and finally serve the resource exploration, environmental dynamic monitoring and planning decision of relevant departments after information processing, interpretation and analysis and field verification. It is a modern science and technology to study the macroscopic laws of the shape, size, position and its correlation with the environment of ground objects through photography or scanning, information response, transmission and processing. Widely used in agriculture, forestry, geology, geography, ocean, hydrology, meteorology, environmental monitoring, earth resource exploration and military reconnaissance. It was used in water conservancy in 1970s.

GIS (Geographic Information System) is a comprehensive spatial information management information computer system developed in recent years. With the support of computer software and hardware technology, it collects, stores, inquires, comprehensively analyzes and outputs information to provide decision support for users. It is a general technology to analyze and deal with problems related to geographical environment such as massive geographical data. Widely used in resource investigation, environmental assessment, regional development planning, public management, traffic safety and other fields. At present, it is playing an increasingly important role in water conservancy.

GPS is a navigation system that can satisfy the time and ranging space. It can give (record) the three-dimensional coordinates of any place on the earth and the running speed of the carrier by receiving satellite information, and can also give accurate time information, which has the function of recording the attributes of ground objects. Because it provides all-weather real-time, high-precision three-dimensional position, speed and accurate time information, it has been widely used in the positioning, navigation and accurate measurement of various military and civilian targets in land, ocean, space and aerospace fields, especially in geodesy, engineering survey, aerial photogrammetry, vehicle navigation and management, crustal movement monitoring, engineering deformation monitoring, resource survey and geodynamics, and has been widely used in the water conservancy industry since the 1990s.

Remote sensing is the basis of data acquisition and updating; Coordinate positioning and local monitoring are the main functions of GPS. Data storage, management, analysis and visualization are the basic functions of GIS. Computer technology is the basis of 3S technology; Network is the wing of 3S; Water conservancy application technology is the driving force of 3S development. 3S technology is widely used in the investigation, monitoring, management and evaluation of water conservancy industry. It is specifically applied to water resources investigation, water environment evaluation, flood control, soil and water conservation, estuary evolution, water conservancy project site selection, reservoir resettlement, etc.

Second, the water conservancy application:

3S technology is like a multi-functional reservoir, which plays a role in centralizing, regulating and purifying information. It contains information from various sources, manages, queries and retrieves data according to geographical and spatial coordinates, and makes scientific processing and decision by means of geographical analysis, spatial analysis, correlation analysis, simulation and prediction, providing multi-level and multi-functional information services. Therefore, 3S technology plays and will continue to play a vital role in water conservancy informatization, that is, water conservancy modernization. 3S technology is mainly used in the following aspects:

Application of 1 in flood control and disaster reduction;

(1) Application of data collection and extraction in rain, water, construction, danger and disaster.

(2) Storage, management and analysis of data and information, that is, flood control and disaster relief information management system.

(3) Flood control decision support such as disaster assessment, evacuation, emergency rescue and disaster relief routes, and quantitative rainfall forecast by meteorological satellites.

2. Application in water resources ecological environment management;

"3S" technology has played an important role in solving the investigation of water resources and ecological environment, dynamically monitoring the changes of water resources and ecological environment, and managing the data of water resources and ecological environment. RS can provide dynamically updated data sources, GIS can provide tools for spatial database management, analysis and application, and GPS can provide spatial positioning basis for water conservancy implementation.

3. Application in soil and water conservation:

RS provides information source for soil erosion investigation, and GIS analyzes soil erosion factors and evaluates soil erosion.

Estimation of erosion type, degree and amount

4. Application in dynamic monitoring of rivers, estuaries and river regime;

Dynamic monitoring of sediment deposition, sediment distribution, rivers, estuaries and river regime.

5, reservoir capacity and lake dynamic change monitoring:

Monitor the change of lake capacity and sediment content.

6, water environment monitoring, evaluation and management:

Water quality monitoring, water environment information management, water environment remote sensing monitoring.

7, drought monitoring, irrigation monitoring and control:

Drought forecast, dynamic monitoring, drought decision support, effective irrigation area and actual irrigation area monitoring, irrigation area planning and dynamic management.

8. Construction and management of water conservancy and hydropower projects

3S is a very important tool in site selection, planning, design and construction management of water conservancy and hydropower projects, such as environmental capacity survey of resettlement sites, route selection and environmental impact assessment of water diversion projects, investigation of cascade development inundation, investigation of reservoir high water level operation inundation, environmental impact assessment of large and medium-sized water conservancy projects, flood control planning, seismic safety of large-scale water conservancy and hydropower projects, river management, storage and transportation management of large-scale water conservancy and hydropower projects, planning and construction of flood storage and detention areas, etc.

9. Disaster assessment mainly includes the following aspects:

Pre-disaster assessment: possible economic losses; People who may be affected (involving social factors); Relocation capacity (number of people, roads, vehicle scheduling); Key protected areas (traffic arteries, important industrial bases, military sites); Storage and transportation of emergency materials. Disaster assessment: determine the disaster situation and development trend; The quantity and transportation route of relief materials; Provide a basis for the decision-making of subsequent flood dispatching schemes; Resettlement of relocated personnel; Preparations for post-disaster reconstruction. Post-disaster assessment: verification of reported losses; Provide information for flood control planning; Provide a plan for post-disaster reconstruction. Outlook:

Under the guidance of the strategic policy of promoting water conservancy modernization by informationization, the application of 3S in water conservancy industry will be "pervasive", it will quickly occupy the management and decision-making level, and it will surely enter the framework of digital watershed or digital water conservancy as the support of basic technology. The main trends of application in water conservancy industry are as follows:

1, network

WebGIS can be used to deal with special data types other than general data, especially vector data. With web browser as the application platform, the vector data operation is realized on the client, and the functions that can only be realized on this machine are realized on multiple clients, and all kinds of data, graphics and images are called and published remotely through the network.

Step 2 synthesize

In practical application, 3S technology not only integrates RS, GIS and GPS strictly, closely and systematically through data interface, making it a large system with more application value, but also closely combines with other systems such as MIS or OA to meet the demand. Therefore, the seamless integration of 3S technology with external systems is an inevitable development trend.

3. Supported by mathematical model and decision analysis.

For water conservancy workers, simply browsing and querying graphics is of little significance. How to make 3S play a greater role in the water conservancy industry, we need to use the unique professional analysis function of 3S software. The water conservancy industry requires the 3S system platform to provide professional analysis algorithms and professional models, and deeply analyze all kinds of water conservancy data, so that the system has the function of assisting decision support and provides scientific calculation results and decision-making basis for relevant departments.

4. Real-time 3D and virtual reality technology.

Many problems in water conservancy are time series problems, dynamic monitoring and process problems. Therefore, the application demand of 3S technology with time dimension is very extensive. Three-dimensional, especially real-time three-dimensional 3S system provides a more intuitive expression for various water conservancy information. It has a wide range of applications or special prospects in the following aspects: the flight of water transmission lines, the flood evolution of cities and flood storage and detention areas, the layout of water conservancy projects, the expression of dam information, the description of geological structure combining ground and underground, the three-dimensional expression of water flow, the description of the inside of factories or structures, the description of reservoir areas, the macro-geomorphological performance, visibility analysis, etc. It is also the basis of virtual or simulation.

5. Standardization

Standardization is portable, interoperable, scalable and universal. Its contents include data, data exchange, database conversion, graphics, software and hardware, as well as geography, algorithm, interpretation and industry standards.

6. Component Geographic Information System

The technical system of GIS software has gone through three stages: GIS module, integrated GIS and modular GIS, and developed into structured GIS stage, that is, based on component platform, a set of communication interfaces with certain standards can realize interaction, even cross-machine interaction. Component GIS makes the software more configurable, extensible and open, more flexible to use, more convenient for secondary development, and especially conducive to the integration and expansion of application systems.

Three. Conclusion:

"3S" is a general term for remote sensing technology RS, geographic information technology GIS and global positioning technology GPS. The "3S" technology is widely used in water conservancy industry, such as water resources investigation, ecological environment management, drought monitoring, irrigation area monitoring and planning, water environment evaluation, flood control and disaster reduction, soil and water conservation, dynamic monitoring of river evolution in estuaries and rivers, site selection of water conservancy projects, dynamic monitoring of reservoir storage capacity and lakes, and reservoir resettlement. With the rapid development of computer technology, the application of "3S" in water conservancy field is more and more extensive and in-depth. The future development direction is bound to be a 3S integrated system with mass data storage function, network function, geographic information modeling function and wireless communication function.

In a word, in order to better apply and develop 3S technology in the water conservancy industry, we must vigorously develop the basic database construction, especially the basic database with the characteristics of the water conservancy industry, such as the social and economic spatial distribution database in flood storage and detention areas, the rain and water regime database, the flood and drought disaster database and so on. In addition, it is necessary to speed up the application level of 3S technology, give full play to the existing and potential functions of 3S, and closely combine it with high-tech such as network computers and the technology of water conservancy industry itself. Make due contributions to the informatization and modernization of water conservancy.