BSc IT Sem VI October 2023 Principles of GIS Question Paper with Solutions

4. People: the analysts, surveyors, programmers and decision-makers who use it.
5. Methods: the procedures and standards by which work is done.

GIScience: the knowledge behind the tool

Geographic information science is the study of the basic questions raised by handling geographic information. Michael Goodchild proposed the term in 1992. It asks how the world should be represented, how accurate the result is, and which methods give sound answers.

Its main themes are:

1. Representation: fields and objects, raster and vector, and how to include time.
2. Reference systems: the shape of the Earth, datums, coordinates and map projections.
3. Data quality: accuracy, uncertainty and how errors spread through analysis.
4. Spatial analysis: interpolation, overlay, network and statistical methods.
5. Visualisation and cognition: how maps communicate and how people understand space.
6. Society: privacy, access to data and the ethics of location data.

How the three fit together

The three form a cycle. GIScience supplies the theory and methods. GISystems put those methods into software. Applications use the software on real problems. Applications then raise new questions, such as how to handle moving objects, which send work back to GIScience.

Worked case: a ward flood map

A municipal ward wants to know which roads flood in heavy rain.

1. Application: the engineer's question, "Which roads are under water after 100 mm of rain?"
2. GISystem: QGIS and a spatial database hold the road layer, the drain network and a terrain grid.
3. GIScience: decides how heights between survey points are estimated (interpolation) and how sure the result is (error propagation).

Conclusion. A GISystem is the tool, and GIScience is the knowledge that makes the tool sound. A GIS application is the tool at work on a real problem. Each improves the others.