Any feature in the physical world is firmly marked by space and time. People's production and life in more than 80 percent of the information and geospatial location. Geographic Information System (Geographic Information System, abbreviated as GIS) as the acquisition, processing, management and analysis of geospatial data as an important tool, technology and discipline, in recent years has been widely concerned and rapid development.
From the point of view of technology and application, GIS is a tool, method and technology for solving spatial problems; from the point of view of discipline, GIS is a discipline developed on the basis of geography, cartography, surveying and computer science, etc., and it has an independent disciplinary system; from the point of view of function, GIS has the functions of spatial data acquisition, storage, present display, editing, processing, analyzing, output and application; from the point of view of systematics, GIS has the functions of spatial data acquisition, storage, presentation, editing, processing, analyzing, output and application. Functionally, GIS has the functions of acquiring, storing, presenting, editing, processing, analyzing, outputting and applying spatial data, etc. From the perspective of systematics, GIS has a certain structure and function, and is a complete system.
In short, GIS is a database management system (DBMS) based on the management of spatial objects of the information system, geospatial data as the object of operation is the fundamental difference between GIS and other information systems.
Components of GIS
From the application point of view, GIS consists of five parts: hardware, software, data, people and methods. Hardware and software provide the environment for the construction of GIS; data is the important content of GIS; methods provide solutions for the construction of GIS; and personnel is the key and dynamic factor in the construction of the system, which directly affects and coordinates several other components.
Hardware mainly includes computers and network equipment, storage devices, data input, display and output peripherals and so on.
Software mainly includes the following categories: operating system software, database management software, system development software, GIS software, and so on. GIS software selection, directly affecting the selection of other software, affecting the system solution, but also affects the system construction cycle and benefits.
Data is the important content of GIS, but also the soul and life of the GIS system. Data organization and processing is the key link in the construction of GIS application system, involving many issues:
--What kind of (or which) scale of data should be selected?
--How current is the existing data?
-Will the accuracy of the data meet the requirements?
-Can the data format be integrated with existing GIS software?
--What methods should be used for processing and integration?
--What methods are used for updating and maintaining the data, and so on.
Methodology refers to the technical route that the system needs to take and the solution that will be used to achieve the system goals. The adoption of the methodology can directly affect system performance and the availability and maintainability of the system.
People are the dynamic part of a GIS system. The technical level of personnel and organizational and management capabilities is an important factor in determining the success or failure of the system construction. System personnel according to different divisions of labor are project managers, project developers, project data personnel, system documentation writing and system testing personnel. Each part of a concerted effort, the division of labor is an important guarantee of the success of the construction of the GIS system.
GIS application system construction needs to start from the above five aspects.
GIS application areas
GIS has made amazing development in the recent 30 years, widely used in resource surveys, environmental assessment, disaster prediction, land management, urban planning, post and telecommunications, transportation, military public security, water conservancy and electricity, public **** facilities management, agriculture, forestry, animal husbandry, statistics, business and finance, and so on, in almost all fields.
The following application areas of GIS answer the role in their respective fields
◆ Resource Management (Resource Management)
Mainly used in the field of agriculture and forestry, to solve the problem of distribution, grading, statistics, mapping of various resources in the field of agriculture and forestry (e.g., land, forests, and pastures). The main answer to the "positioning" and "mode" two types of questions.
◆ Resource Configuration (Resource Configuration)
In the city in a variety of utilities, disaster relief and mitigation in the distribution of materials, nationwide energy security, food supply and other institutions in the configuration of the local are resource allocation issues. GIS in this type of application is to ensure that the goal of the most reasonable allocation of resources and play the maximum benefit.
◆Urban Planning and Management (Urban Planning and Management)
Spatial planning is an important application of GIS, and urban planning and management is one of the main content. For example, how to ensure the proportion and reasonable distribution of green space in large-scale urban infrastructure construction, how to ensure that schools, public **** facilities, sports venues, service facilities, etc. can have the largest service surface (urban resource allocation issues).
◆ Land Information System and Cadastral Applicaiton (Land Information System and Cadastral Applicaiton)
Land and cadastral management involves changes in the nature of the use of land, changes in the contour of the land parcel, cadastral tenure changes and many other things, with the help of GIS technology can be efficient, high-quality completion of these tasks.
Land and cadastre management involves changes in the nature of land use, changes in the contours of land parcels, and changes in cadastral relationships.
◆ Ecology, environmental management and modeling (Environmental Management and Modeling)
Regional ecological planning, environmental status evaluation, environmental impact assessment, decision support for pollutant reduction and distribution, decision support for environmental and regional sustainable development, management of environmental protection facilities, environmental planning.
◆ Emergency Response (Emergency Response)
To solve the problem of how to arrange the best evacuation routes and equip the corresponding transportation and security facilities in the event of major natural or man-made disasters such as floods, wars, and nuclear accidents.
◆ Application in GeoScience
Topographic analysis, watershed analysis, land use research, economic geography, spatial decision support, spatial statistical analysis, cartography, etc. can be accomplished with the help of GIS tools.
◆ Business and Marketing (Business and Marketing)
The establishment of commercial facilities to fully consider its market potential. For example, if a large shopping mall is built without considering the distribution of other shopping malls and the distribution and number of people living in the surrounding neighborhoods of the area to be built, it may not be able to achieve the expected market and service surface after completion. In some cases, even the variety of products to be sold in the shopping mall and the market orientation must be considered in conjunction with the demographic structure (age, gender, literacy level) and consumption level of the area to be built. The spatial analysis and database functions of GIS can solve these problems. Real estate development and sales process can also use GIS functions for decision-making and analysis.
◆ Infrastructure management (Facilities Management)
City infrastructure above and below ground (telecommunications, water, road traffic, gas pipelines, sewage facilities, electric power facilities, etc.) are widely distributed in all corners of the city, and these facilities are clearly geo-referenced characteristics. Their management, statistics, summary can be completed with the help of GIS, and can greatly improve efficiency.
◆ Site Selecting Analysis (Site Selecting Analysis)
According to the characteristics of the regional geographic environment, taking into account the allocation of resources, market potential, transportation conditions, topographic features, environmental impact and other factors, to choose the best location within the region, is a typical application of GIS, fully embodies the spatial analysis of GIS functions.
◆ Network Analysis (Newwork System Analysis)
Establishing a computer model of the transportation network, underground pipeline network, etc., to study the traffic flow, carry out traffic rules, and deal with underground pipeline emergencies (burst pipe, broken road) and other emergency treatment. Police and medical rescue path selection, vehicle navigation, etc. is also an example of GIS network analysis applications.
◆ Visualization Application (Visualization Application)
Based on the digital terrain model, the establishment of the city, region, or large-scale construction projects, three-dimensional visualization of the famous scenic spots model, to achieve a multi-angle browsing, can be widely used in publicity, urban and regional planning, management and simulation of large-scale projects, tourism and other fields.
◆ Distributed Geographic Information Application (Distributed Geographic Information Application)
With the development of network and Internet technology, running on the Intranet or Internet environment, the type of geographic information system applications, the goal is to achieve the following Distributed storage of geographic information and information **** enjoyment, as well as remote spatial navigation.
GIS software
Foreign:
ArcGIS (including ArcGIS, MapObjects, ArcIMS, ArcSDE, etc.)
MapInfo
GeoMedia
MGE
SmallWorld
Domestic:
Supermap
MapGIS
GeoStar
TopMap
GeoBean
VRMap
MapEngine
GIS in the Electric Power Industry
In the power industry, GIS refers to the sulfur hexafluoride enclosed combination of electrical appliances, internationally known as "gas insulated switchgear" (Gas Insulated Switchgear) referred to as GIS, which will be a substation in addition to the transformer in the primary equipment, including circuit breakers, disconnecting switches, grounding switches, Voltage transformer, current transformer, lightning arrester, busbar, cable terminals, inlet and outlet casing, etc., by optimizing the design of the organic combination into a whole.
GIS full name of the gas insulated combination of electrical equipment (Gas Insulated Switchgear), the main bus, circuit breaker, CT, PT, disconnecting switch, lightning arrester are combined together. That is we can often see the switching station, also called high-voltage power distribution equipment.
There are three types of high-voltage power distribution: the first is the air-insulated conventional power distribution, referred to as AIS. the busbar is exposed directly in contact with the air, the circuit breaker can be used in porcelain columns or cans. Gezhouba power plant is used in this type. The second is a hybrid power distribution device, referred to as H-GIS, the busbar is open, the other are sulfur hexafluoride gas-insulated switchgear. The third type is sulfur hexafluoride gas-insulated fully enclosed distribution equipment. Its full English name GAS-INSTULATED SWITCHGEAR, referred to as GIS.
The advantages of GIS are small footprint, high reliability, security, maintenance workload is very small, and the maintenance interval of its main components is not less than 20 years.