tailieunhanh - Practical GIS Analysis - Chapter 6

Phân đoạn thị trường năng động là một loại đặc biệt của phân tích dòng. Arcs được phân đoạn tự động và tạm thời để phân tích. Năng động, phân khúc đặc biệt hữu ích trong các tình huống khi vòng cung được sử dụng cho nhiều ứng dụng khác nhau. Ví dụ, hãy tưởng tượng rằng bạn có một vòng cung từ một chủ đề đường phố: Các bộ phận bảo trì đường phố muốn phân đoạn các đường phố mới dựa vào loại vỉa hè | Chapter 6 Dynamic Segmentation INTRODUCTION Dynamic Segmentation is a special type of line analysis. Arcs are segmented dynamically and temporarily for the analysis. Dynamic segmentation is especially useful in situations when arcs are used for many different applications. For example imagine that you have an arc from a streets theme The street maintenance department wants to segment the street based on pavement type. PAVED GRAVEL The police department wants to segment the street based on speed limits. 25 MPH 45 MPH 35 MPH And the fire department wants to segment the street based on hydrant locations. You can see that the arc becomes quite segmented and complex with these three applications . . . ---------------------- --------- -e An alternative is to maintain the original streets theme and use dynamic segmentation for each application. Dynamic segmentation has another advantage it does not require X Y coordinates of events that are used to segment an arc. You can use events such as accidents with distance from an intersection interpretive stops with highway mile markers and so on. This type of linear data is called route-measure formatted data. 77 2002 Taylor Francis 78 Practical GIS Analysis ROUTES AND SECTIONS A route is a collection of arc segments or sections which have attributes. A route does not necessarily have to start or end at a node. The following might be an example of a bus route. BUS ROUTE And a collection of routes is called a route system. The following is an example of a route system composed of three bus routes. BUS ROUTE 1 BUS ROUTE 2 BUS ROUTE 3 Each route is composed of one or more sections. For example assume you have a road route 19 that has three sections dirt from mile 0 to mile gravel from mile to and paved from mile to 10. This could be represented as a route with the following section attributes ARC 6 . ARC 5 Route Attribute Table Route Route-ID 1 19 Section Attribute Table Arc Routelink F-Meas T-Meas F-Pos T-Pos .