GIS is a discipline that has evolved with the development of geographic science, computer technology, remote sensing technology, and information science. In the history of computer development, in the history of computer development, the emergence of computer-aided design technology (CAD) makes it possible to use computers to deal with data like graphs, one of the hallmarks of graphical data is that graphical elements have clear positional coordinates, and that there are a variety of topological relationships between different graphs. Simply put, topological relationships refer to the spatial locations and connections between graphical elements. Simple graphical elements such as points, lines, polygons, etc.; points have coordinates (x, y); lines can be viewed as consisting of an infinite number of points, and the position of a line can be expressed as a series of coordinate pairs (x1, y1), (x2, y2), ...... (xn, yn); polygons on the plane can be thought of as ranges formed by closed curves. There are a variety of interrelationships between graphical elements, such as a point on a line or within a polygon, a line through a polygon, and so on. In practice, a GIS has to manage very large and complex data, perhaps tens of thousands of polygons, tens of thousands of lines, tens of thousands of points, and has to calculate and manage a variety of complex spatial relationships between them .......
GIS is the integration of computer hardware, software, geographic data, and system administrators organized to efficiently acquire, store, update, manipulate, analyze, and display any form of geographic information.
GIS technology is widely used in agriculture, forestry, land resources, mining, military, transportation, mapping, water conservancy, radio and television, communications, electricity, public security, community management, education, energy and other almost all industries, and is into people's daily work, study and life.
The main computer hardware of geographic information systems are workstations and microcomputers. Geographic information system of the main computer operating system software is UNIX, Windows9X, Windows NT, Windows2000, Macintosh and so on.
The main computer application software for GIS is ARC/INFO, MGE, GeoMedia, GenaMap, MapInfo, AutoDesk Map, ArcView, MapObjects, MapX, Maptitude, MapGIS, GeoStar, MapEngine, etc.
The main basic geographic data scales of GIS are 1:4 million, 1:1 million, 1:250,000, 1:50,000, 1:10,000, 1:2,000, 1:1,000, 1:500, etc.; the types of basic geographic data are Digital Line Graph (DLG), Digital Raster Graph (DRG), Digital Orthophoto Quadrangle (DOQ) and Digital Elevation Model (DEM). DEM), etc.
GIS GIS-related technologies
GIS is closely related to several other information systems, but is set apart from them by its ability to process and analyze geographic data. Although there are no hard and fast rules for categorizing these information systems, the following discussion can help distinguish GIS from desktop mapping, computer-aided design CAD, remote sensing, DBMS, and GPS technologies.
Desktop Mapping
Desktop mapping systems use maps to organize data and user interaction. The main purpose of such systems is to produce maps: the map is the database. Most desktop mapping systems have only limited data management, spatial analysis, and personalization capabilities. Desktop mapping systems operate on desktop computers such as PCs, Macintosh, and small UNIX workstations.
Computer-Aided Design CAD
Computer-aided design (CAD) systems facilitate the design and planning of generating buildings and infrastructure. Such designs require the assembly of inherently characterized components to produce the entire structure. These systems require rules to indicate how to assemble these components and have very limited analytical capabilities.CAD systems have been extended to support map design, but tools for managing and analyzing large geodatabases are limited.
Remote Sensing and GPS
Remote sensing is the science and technology of measuring the Earth using sensors, such as cameras on airplanes, Global Positioning System (GPS) receivers, or other devices. These sensors collect data in a graphical format and provide specialized capabilities for exploiting, analyzing, and visualizing these images. Because it lacks a strong geographic data management and analysis role, it can't be called a true GIS.
DBMS Database Management Systems
Database management systems specialize in storing and managing all types of data, including geographic data.DBMSs optimize storing and finding data, and many GISs rely on them for this purpose. In contrast to GIS, they do not have tools for analysis and visualization.