GIS is used as part of analysis concerning residential and job locations of bus and motorcycle users. Originally, GIS data were obtained at a sub-district level from a larger map of Central Thailand (courtesy of Thailand Environmental Institute -  But due to limitation of survey data, the analysis can be performed only at the district level. Therefore, the sub-district data need to be converted to the district level data. The first screen shows a map of Central Thailand, which are comprised of polygon data. Each polygon represents a sub-district in Central Thailand. 
The next screen shows the area of interest for this project, which is Bangkok. Bangkok is a province in the central region of Thailand. 
The next screen zooms to the map of Bangkok level. Again, these are polygon data. Each polygon is a sub-district of Bangkok. 
Since the survey data collected from bus and motorcycle users in Bangkok are in the district level, not the sub-district level, the "Dissolve" feature in ArcView is used to combine polygon data together and create a new district-level data, where each polygon represents each of the 50 districts in Bangkok. 
The next screen shows both the original sub-district data and the district data after dissolving features is done.