最近几年来，地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持，如城市管理、区划、环境整治等等，地理信息成为信息时代重要的组成部分之一； “数字地球”概念的提出，更进一步推动了作为其技术支撑的GIS的发展。 与此同时，一些学者致力于相关的理论研究，如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面，并且这两个方面构成了相互促进的发展过程。
发布时间 ： 2023-08-23 01:42:48 UTC
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Geographic information systems usually establish spatial databases based on meaningful layers and corresponding attributes. In order to meet the needs of specific spatial analysis, a series of logical or algebraic operations on the original layer and its attributes are needed to generate new geographical layers with special meanings and their attributes, this process is called spatial transformation. Spatial transformations can be based on a single layer, or on multiple layers, this chapter limits spatial transformation to operations or calculations on a single layer, multi-layer operations are described in overlay analysis.
Spatial data in GIS can be divided into vector and raster data structures. Due to the vector structure contains a lot of topological information and the data organization is complex, the spatial transformation is very complicated. The grid structure is simple and regular, and the spatial transformation is easy. In addition, the space transformation based on vector structure is of little significance to a single layer, when generating a new layer, the information of multiple layers is often needed, which is of great significance in multi-layer overlay analysis.
Spatial transformation based on grid structure can be divided into three ways: (1) single point transformation; (2) neighborhood transformation; (3) region transformation.
Single-point transformation only considers the attribute value of a single point, and assumes that the transformation of an independent unit does not depend on the attributes of its neighbors, nor is it affected by the general characteristics of the region. The most common functions of single point transformation are algebraic operations such as addition, subtraction, multiplication and division, logical operations such as sum, union, non-exclusion or exclusion, comparative operations such as greater or less, exponential functions, logarithmic functions, trigonometric functions, etc. The new layer can be completely different from the original layer.
The neighborhood transform means that when calculating the value of a new layer primitive, not only the value of the corresponding primitive itself on the original layer, but also the influence of other primitive values associated with the primitive. This association can be a direct geometric association or an indirect geometric association. Common functions include smooth, discrete point search, continuous surface description (slope, aspect, visual field analysis), point judgment in polygons, etc.
The area transformation means that when calculating the value of a new layer attribute, the attribute value of the entire area is considered, that is, a function is used to synthesize all the values in a certain area, and then the new attribute value is calculated. Common functions include methods such as region mean, mode, extremum, summation, grouping, and overall interpolation.
最近几年来，地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持，如城市管理、区划、环境整治等等，地理信息成为信息时代重要的组成部分之一； “数字地球”概念的提出，更进一步推动了作为其技术支撑的GIS的发展。 与此同时，一些学者致力于相关的理论研究，如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面，并且这两个方面构成了相互促进的发展过程。