GIS Basic Concept Color
GIS Basic Concept Collection 1, Geographic Information System, That is, GIS - a new discipline with a variety of science such as computer science, informationchilology, geography, is under computer software and hardware support, Application of system engineering and information science theory, scientific management and comprehensive analysis of geographic data with space connotation to provide space information systems for planning, management, decision making and research needs. GIS is under sub-system: data input subsystem, data storage, and search subsystem, data operation and analysis subsystem, report subsystem. Information system non-space space management information system Non-geography GIS CAD / CAM Other GIS Lis Social economy, census is based on non-block, based on plotting 2, compared to GIS and CAD, and CAC. CAD - computer aided design, generation of rules graphics, editing and display system, independent of external description data. CAC - computer auxiliary drawing, special software suitable for map mapping, lacks spatial analysis capabilities. GIS - geographic information system, collection rules graphic and map mapping maps, and have strong spatial analysis capabilities. 3. Layers: The space information is divided into its geometric characteristics and attributes. 4, geographic data collection - field survey, sampling; traditional measurement method, triangular measurement method, trilateral measurement method; global positioning system (GPS); modern remote sensing technology; biotechoscope; digital photography technology; census. 5, Information Example - Traditional mapping method, called information example, that is, the map itself is a final product, swapping spatial information mode by using symbols, classification restrictions, etc.. This example is a traditional perspective method that is subject to many restrictions, and the map user cannot easily obtain pre-clasable data. That is, the user is limited to the processing of the final product, and the data is unable to restructuring the data in a more efficient form to adapt to the environment or demand. 6. Analysis Example (Overall Example) - Store the properties data of the original data, and can be displayed, reorganized, and classified according to the needs of the user. Overall examples are a true method for graphics and geography. 7, raster-grid structure is the simplest and most direct spatial data structure, refers to a grid array that divides the earth's surface into even uniform and tight adjacent grid, each grid as a vowel or pixel. Columns definitions and include a code indicating the type or magnitude of the pixel, or only including a pointer to its property record. Thus, the grid structure is a data tissue that represents a spatial object or a phenomenon distribution in a regular array, and each of the tissues represents a non-geometric attribute feature of the object or phenomenon. Features: The property is obvious, the positioning is implicit, that is, the data is directly recorded in the property itself, and the location is converted to the corresponding coordinate according to the line ranking number, that is, the positioning is obtained according to the position in the data set, in the grid structure, point Use a raster unit; a set of adjacent grid units along the line-like, each grid unit has only two adjacent units on the line; the surface or region is a memory adjacent The set of raster units represents more than two adjacent units of each grid unit. 8, vector - it assumes that the geospatial is continuous, and the coordinate, the coordinates are accurately expressed as accurately, the coordinate space is set to continuous, allowing precise definitions of any position, length, and area. For point entities, only the coordinates and attribute code in a particular coordinate system are recorded in the vector structure; for the line entity, a series of coordinate pairs is represented; the polygon is a spatial area that is completely closed by the boundary, with a series of coordinate pairs The connection is represented.
9. The word "topology" comes from Greek, its original intention is "research on shape". Topology is a branch of geometry, it studies the geometric property-topology attribute (topology properties: a point in one extension, a point in one area; non-topology) Attribute: The distance between the two points, the length of the arc, the circumference of the area, area). This structure should include: unique identifier, polygon identification, outsourcing polygon pointer, adjacent polygon pointer, boundary link, range (maximum and minimum x, y coordinate). Three important topology concepts in geospatial research (1) Connectivity: The intergeneration relationship of the arc is at the node; (2) Polygon area definition: The plurality of arc segments constitute the internal area of the polygon; (3) Adjacent: By defining the left and right sides and direction of the arc segments and their directionality to determine the neighborhood of the left and right polygon. 10, vector entity error - pseudo node: Nodes that need to be identified, where there is a place to connect online, such as island-shaped pseudo knot - display there is an island-shaped polygon, this polygon is in another Large polygonal inside), or where the two lines intersect along the parallel path rather than the cross path (node - represents a special point between the line and the line). Swing Node: Sometimes it is called a swing, from three possible wrong types: closed failed polygon; an incarnated point, that is, the extension of the point is not enough, not connected to the target should be connected; overhead line, the line of the node is exceeded I want to connect with it. Crushed polygon: from the bad digitization process in the common boundary line, in the boundary line position, the line must not only digitize once. Highly irregular national border lines, such as Central America, particularly prone to such digital deformation. Note error: Lost labeling and repeated marking. Abnormal polygon: a polygon with a lost node. Lost arc. 11, spatial analysis method - 1, spatial information measurement: measurement, distance measurement, shape measurement of lines and polygons; Space information classification, neighborhood function, roaming window, buffer; 3, superposition analysis : Polygonal stack, point and polygon, line and polygon; 4, network analysis: path analysis, address matching, resource matching; 5, spatial statistical analysis: interpolation, trend analysis, structure analysis; 6, surface analysis: slope analysis, slope Analysis, visibility and mutual visibility analysis. 12, Euler number - the most common spatial integrity, the number of empty spaces in the void area, the measuring method is called the Euler function, which describes these functions using only a single number, called the Ou Rax. On the number, the number of Euler = (empty cavity) - (the number of pieces) Sometimes the number of Euler is uncertain. 13. Function distance - a functional relationship of two point distances, such as time, friction, consumption, etc., focusing these methods for distance measurements, called function distance. 14, Manhattan Distance - Two points in the north and south direction plus the distance in the east and west direction, ie D (I, j) = | xi-xj | | yi-yj |.
For a town street with the rule layout of Zhengnan Zhengbei, Zhengdong Zhengxi, from the distance to another, is the distance from the north and south, plus the distance of traveling on the east and west, therefore, Manhattan is also known as The taxi distance, the Manhattan is not a distance invariant. When the axis is changed, the distance between the points will be different. 15. Neighborhood function - The so-called neighborhood refers to a small part of the physical space with a solid area or focus of the unified attribute. The neighborhood function is the consistency of its properties in a particular physical space. It includes direct neighborhood and expansion neighborhoods. 16. Buffer analysis - means that the buffer polygon entity in which it is automatically established according to the point, line, and surface entity foundation of the database, and the spatial analysis method of space data is extended in the horizontal direction. The buffer is controlled to some extent, which is currently existing friction surface, terrain, obstacles, etc., that is, although the buffer is based on the position, there is other substantial ingredients. Four basic methods of determining the distance of the buffer: Random buffer, resulting in a buffer, measuring buffer, legal authorization buffer. 17. The statistical surface-surface is a topography containing the Z value, and the Z value is also known as a height value, and its position is defined by a series of X and Y coordinates and distributed within the region. The z value is often considered a high degree, but it is not necessary to limit this measure. In fact, any of the measurable values (e.g., ordinal numbers, intervals, and ratio data) that appear in a defined area can be considered to form a surface. The term generally used is a statistical surface because the Z value is constituted in consideration of the statistical representation of many elements (Robinson et al., 1995). 18, DEM - Digital Elevation Model. The terrain model not only contains elevated attributes, but also other surface morphological properties such as slope, slope, etc. DEM usually uses an elevation matrix constituted by the land rules grid unit, and the broad DEM also includes a digital representation of all expressions such as contour lines and triangular webs. In the geographic information system, DEM is the basic data of Digital Terrain Model, and other terrain elements can be exported directly or indirectly from DEM, called "derived data", such as slope, slope. 19. Space Interpolation - Space Interpolation is often used to convert the measurement data of the deposited point into a continuous data surface to compare with the distribution mode of other spatial phenomena, which includes space interpolation and external pushing algorithm. Space interpolation algorithm: Separate the same area unknown point data by a known point. Space External Extension Algorithm: Data of other area data by data in known regions. 20, Tyson Polygon - Defined by mathematical methods, space between flat points and linearly in line, forming a polygon between dot objects. 21, line density - divided by the total length of the line in all regions. 22, connectivity - connectivity is a measure of metrics of network complexity, often calculating it with the γ index and α index. Among them, the γ index is equal to the ratio of all the number of links of the given spatial network, and the number of all connect numbers may exist; the α index is used to measure the loop, and the node is alternating the path connection is referred to as an alpha index, equal to the current ring. The ratio of the number of roads and the maximum number of loops that may exist. 23. Graphics superimposed - Place the topic information represented by one selected subject on the topic information indicated by another selection topic. 24. Raster automatic superimposition - The multilateral laminated grid unit is a simple process because the area is an irregular block consisting of the grid unit, which shares the same set of values and related labels. There is no doubt that the grid unit-based multilateral superposition lacks spatial accuracy because the grid unit is large, but similar to the simple point and the same part of the polygon and the multilateral stack, because of its simplicity, it can be obtained Higher flexibility and processing speed.
25. Topological vector superposition - how to determine the functional relationship between the entity, such as defining the left and right polygons connected by special lines, defining the relationship between the line segments to check traffic flow, or search for the selected entity according to individual entities or related attributes. It also establishes a method for superimposing multiple polygonal layers, ensuring that the properties of each entity can be considered, and thus the synthetic polygon that combines multiple attributes can be supported. This topology is called the minimum public geographic unit (LCGU). 26. The main problem with the vector multilateral laminated-point and polygon and line and multilateral combination is that the line does not always appear in the entire area. The most powerful way to solve this problem is to let the software determine the intersection of each set of lines, which is the so-called node. The stack of vector polygons is made substantially the same, in addition to calculating the overlapping intersection, defining the properties of the polygon line associated therewith. 27, Boolean overlay - a superimposed operation based on the Boolean. 28, Drawing Modeling - To specify the application command combination to answer the processing of spatial phenomena issues. The drawing model is a series of interactive or orderly map operations to simulate space decisions for raw data, including exporting data and intermediate map data. 29. Types of geographical model - similar statistics and similar descriptive models and regular models related to reasoning statistics technology. 30. Common models - 1, focusing on styles and processing problems for long-term relationship between similar agricultural activities and transportation costs - independent state models. 2, the Weber model designed to predict the spatial distribution of industrial location points, enabling participants to find the best business and service location-position-allocation model. 3. Establish an economic geographical model - gravity model based on the distance between attractive and potential market. 4, through spatial verification ideas, now widely used in the ecological community, through geospatial tracking, animal and plant motion - improve the diffusion model. 31, Topics Map - Map of relationship between a single property or a number of selected properties. The general procedures for the topic graphics include the selection, generation, and placement of the appropriate symbols and graphics objects to clearly highlight important attributes and spatial relationships of the research topics, while also considering the reference system. GIS topic map output rules: not only have a beautiful graph, the most important thing is to read the map, analyze the map and understand the map. 32, metadata - data on data, a comprehensive description of database content, the purpose is to promote efficient utilization and full sharing of data sets. Reasons for using metadata: performance, integrity, scalability, specialty, security, feature, error function, browsing, program generation. 33. Polymerization - a large number of digital processing processes that classify a single data element. 34. Kelgin Law - A precise interpolation method of the elevation with the probability of the natural surface with the distance. 35, quadtree - a compressed data structure, which divides geospatial quantities into variable size mesh, each grid having the same properties. 36. The difference between the tool type geographic information system and the application type geographic information system. Tool type Geographic Information System: It is a general purpose GIS, with general functions and features, providing users with a unified operational platform. There is generally no geospatial entity, but is defined by the user. Have a good secondary development function. As: Arcinfo, Genamap, MapInfo, Mapgis, Geostar. Application Geographic Information System: Based on the more mature tool type GIS software, based on the user's needs and application purposes, it is a geographical spatial entity and solving special. Model of geospatial distribution. Such as LIS, CGIS, UGIS.
