Comparison of GIS computational methods using real life spatial data : Building and population density computation in a semi urban area

Abstract

Spatial data sets are developed for various purposes, with different software and by resource personnel who have varying skill levels.

Though these data sets are often adequate for visualization of spatial variations, they pose significant problems in case of attempts to perform even simple GIS computations. This problem of different data origin, faced by GIS experts when preparing base data sets for modelling, consumes a significant time which is usually not properly appreciated by the managers or decision makers. When such irregular data sets are suitably identified, adjusted, and incorporated appropriately, GIS computations would become a simple routine exercise.

The present work is a corporative assessment of the computation of building area density and the population density in a semi urban area of approximately 25km2 near the city of Colombo, Sri Lanka. Population density is a simple computation carried out by identifying the number of people living on land extents which could be occupied for dwelling. Building area density computation too is a straight forward computation executed with the identification of the area occupied by buildings in comparison with the area available for building purposes.

The present work in a step by step manner describes the methodology used for each computation, the associated problems, encountered constraints, steps taken to overcome the issues and recommended techniques to carrying out similar works.