Figure 6 operational layers consist of but are not

This preview shows page 20 - 23 out of 30 pages.

Figure 6 Operational layers consist of, but are not limited to: Observations or sensor feeds : This can be any information that reflects status or situational awareness, for example, taxi locations, Wi-fi hotspot coverage feeds, real- 20
time air quality, location status from railway, observations from equipment or made by workers in the field, and addresses of schools. These information sources are often displayed as status information in web GIS maps. Also, they are frequently used as inputs into analytic operations that are computed on the server. Figure 7 Editing and data access layers : These are the map layers that your users work with, for example, to edit features, perform queries, and select features for input to analysis. Query results : In many cases, applications will make a query request to the server and return a set of records as results. These can include a set of individual features or attribute records. these results are displayed as map graphics in the web GIS applications. Result layers that are derived from analytic models : GIS analysis can be performed to derive new information that can be added as new map layers and explored, visualized, interpreted, and compared by end users, such as the taxi station 200 meters service area in Kowloon East. In this GIS applications, users can work with operational information on top of the basemap, which provides the geographic context. Operational layers are often dynamic; they are retrieved from the GIS database and displayed during runtime, for example, each time you pan, zoom, or refresh your map. It is common that operational layers work within a focused range of map scales and resolutions. 21
iv. Tasks and tools in the web GIS application Web GIS applications often provide tools that perform processes beyond mapping. These tools range from common types, such as finding school addresses. There are two ways to run the tasks: Have the client do it : This method fits processes that are relatively easy and when the data needed is all on the client side. Typical examples include generating heat maps based on a set of point features. Have the server do it: This fits processes that are complex and when the data needed is not housed on the client side. Typical examples include finding and routing to the closest facility. Many end users have a set of target layers and an associated set of tools to work with those layers, for example, to perform point pattern analysis on a set of Wi-Fi___33 locations. For sensor feeds, there are often sets of tools for displaying, summarizing, graphing, and analyzing feeds from the field such as air quality index. Another function in web GIS applications is that the users can submit queries and comments to the server, which returns a set of features and their attributes. These results are displayed on the map as interactive graphics and descriptive information that can be charted, summarized, and hyperlinked to more detailed information.

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture