TOPOLOGY’S CONTRIBUTIONS

          

          Topology’s contributions offers a number of advantages and contributions to geographic data and GIS, Which are depicted as following.

  

Spatial Information: Topology provides length, distance, perimeter, and area. Resulting from topological calculations.

  

Spatial Relationship: Topology creates connections, which functionally link features that are djacent, such as the province in Sri Lanka. A query asking MATALA province adjoining provinces, Kurunagala, Kandy, …..

Multiple linkages: Each feature is linked to other features, providing multiple connections (linkages) that join (unite) them. Image show the polygon adjacency connections from Kurunagala, Mathale, Kandy.

Network analysis: The functional connections, distance, and other spatial relationship, combined with the relational database, are ideal in interpreting network features (Such as highway system), and for performing specialized analysis (Shortest route).      

GIS DATA ACQUISITION

There are many source of GIS data acquisition.

q       Maps

q       Field Data

q       Digital Product

q       Tabular Data

q       Human Input

q           Remote Sensing

Maps

Maps, the most common presentation of spatial data, are primary source for most GIS projects. Just about every type of maps can be digitized in to GIS.

Field Data

Data collected in the field (study area) is considered “primary” data, which refers first observation put into database, typically unprocessed regarding classification or meaning. This involves notes and photographs put into the database in GIS.                       

Digital Products

Digital products, which are sets of processed data ready to use, are available from various organizations and commercial sources. They may be database, image, maps, or any type of data or information that can be integrated into GIS.

Reports

Reports can be translated into useful data by manual entry or scanning, some reports and their data are stored on CD-ROM or Internet. These data more accessible and useful.

Human Input

Human input, such as decisions concerning classifications, can also be included in GIS. This is an important flexibility of GIS because judgment, interpretations or personal knowledge can be as valuable as field data.

Remote Sensing

Remote sensing is the collection of landscape data from above, such as by aircraft carrying cameras and electronic sensors, and space vehicles. Remote sensing is a major source of GIS data, and with a little work imagery can be placed directly into the GIS database.