Principles of GIS (Peter)
Chapter 7: analysis of discrete entities in space
本章将主要针对entities in space
1. 不同类型的数据模型与不同类型的表现形式需要不同的处理方法，最基本的分类是：
a. entities in space: concern the attributes, location and connectivity of the entities and measures of the way they are distributed in space
b. continuous variation of an attribute over space: concerns the spatial properties of the fields (较为复杂因为：连续场通常被离散为一组三角形或规则网格，网格单元的单个三角形也可以被视为单个实体)
2. operations的分类
查下lecture1讲义里面用到的名字，三个至关重要的问题都对应着不同的决定因素：
- what is it: attribute
- where is it: geographical location or coordinates
- what is its relation to other entities: proximity and connectivity (topology)
operations可以分为attribute operations(会根据attributes之间的关系逐步细分，看书128), distance/location operations, operations using built-in spatial topology
3. attributes can be divided into 3 types:
a. those refer to location
b. those simply attached as qualitative or quantitative descriptors of some non-spatial properties作为一些非空间性质的定性或定量描述符附加的
c. those are derived from the spatial properties of the entity itself
An introduction (Van Niel)
Chapter 9: Vector Geoprocessing tools
- Geoprocessing tools form part of the GIS toolbox and are specifically designed for the manipulation and analysis of spatial and attribute data, which alter pre-existing data to create new layers and attribute tables.
- Introduction about some tools:
a) Buffering: creates an area(polygon) around a feature, the result of any buffering process is a new polygon layer
b) Erasing(deleting): can be divided into one layer; two pre-existing layers (deletes data from one layer, defined by data in the second layer, to create a third, new layer)
c) Extracting: maintaining only specified areas
d) Merging: creates a new layer, based on data in an existing layer, by removing unnecessary of superfluous polygon boundaries (generalising)
e) Updating: common process in dynamic datasets, which allows spatial and attribute data associated with a section of the layer to be updated, based on new or more relevant data
f) Vector overlay: 将一个数据层直接放置或叠加在另一个数据层上，以探索数据中的关系和关联, the overlay procedure differs between vector and raster data. Boolean operators are the most widely used type of vector overlay, sometimes overlay operation may be a mathematical operator as well(such as addition)