Question

Write an explanatory account of the sequence of activities involved in GIS related work.

Answer 1

The following sequence of activities are involved in GIS-related work:

1. Spatial data input: Under this data, which is collected from different people, is tested, and it is checked whether they are suitable for the investigator or not.
2. Entering the attribute data: Attribute data defines the properties of a spatial entity that need to be handled in the GIS, but which are not spatial. For example, a road may be captured as a set of contiguous pixels or as a line entity and represented in the spatial part of the GIS by a certain colour, symbol, or data location.
3. Data verification and editing: The spatial data captured into a GIS requires verification for error identification and corrections so as to ensure data accuracy. The errors caused during digitisation may include data omissions and undershoots. The best way to check for errors in the spatial data is to produce a computer plot or print of the data, preferably on the translucent sheet, at the same scale as the original. The two maps may then be placed over each other on a light table and compared visually, working systematically from left to right and top to bottom of the map. Missing data and locational errors should be clearly marked on the printout.
4. Spatial and attribute data linkages: The linkages of spatial and attribute data are important in GIS. It must, therefore, be carefully undertaken. Linking attribute data with non-related spatial data shall lead to chaos in ultimate data analysis. Similarly, matching one data layer with another is also significant.
5. Spatial analysis: The objective of the geographic analysis is to transform data into useful information to satisfy the requirements of the decision-makers. It requires step-by-step procedures to arrive at the conclusion. The following spatial analysis operation may be undertaken using GIS:
   1. Overlay analysis
   2. Buffer analysis
   3. Network analysis
   4. Digital terrain model