SMT201 AY2019-20G2 Ex2 Lu Zhimao
Contents
Part One: A map layout with four views
The study area and the target roads
Using Selection by Location feature, I extracted the roads that falls within Gombak study area, followed by the filtering of roads to sieve out the relevant roads namely – service and track which are depicted by the colors blue and purple respectively. There are a total of 199 services roads and 2 track roads where most of the roads are located towards the right-hand side of the study area.
The study area and buildings
Using Selection by Location feature, the extraction of the buildings is done. Buildings are generally in clusters except for a few which are built at a higher elevation. The buildings located at the lower elevations might be more easily accessible by more roads due to lesser slopes and more road connections as opposed to the buildings at the higher elevation. Most of the buildings located at the lower elevation tend to have more facilities located near them such as parks, roads and water bodies compared to those buildings at the higher elevation. However, those buildings at the higher elevation would have a better overview.
The Study area and the target natural features
After extracting Naturals which falls within the Gombak study area through the Selection by Location feature function, I have identified 3 water bodies, 1 forest and 4 parks. The water body, forest and parks are represented by the colors light blue, green and darker pink respectively. All the natural attractions are located away from the center of the study area due to the elevation level.
The study area and digital elevation
The highest elevation points fall in the lower-center parts of the Gombak study area which is 145m above sea level and the lowest elevation points fall in the top, left and right parts of the Gombak study area which is 8m above sea level. Most of the roads, buildings and natural attractions tend to build at a relatively lower elevation level apart from the five buildings which are built at the highest elevation. An important information to take note of is that during the process of creating slope layer, the QGIS system tends to auto-remove one row of pixels away from each side of the Aster_GDEM layer. In order for the slope layer to cover up the entire study area, when extracting clip raster by extent the clipping extent (xmin, xmax, ymin,ymax) has to be adjusted to a slightly bigger scale so that even after creating the slope layer the study area will still falls within the slope layer.
Part Two: A map layout with four views(Proximity)
the study area and Proximity to target roads layer
The distance from land lot to the nearest road is 0m and represented by blacks and furthest distance is 791.281m and represented by the whites. By looking at the color we can determine where is the ideal location to build the quarantine building on the requirement. As mentioned in the above, due to the accessibility factor, we should build the building nearer to the roads hence we should pay more attention to those areas represented by the blacks. Areas in whites are not as accessible because there are either no road or lesser roads as compared to the area in blacks as it is located further away from the roads, which might not be the ideal location to build the quarantine building.
the study area and Proxmity to target natural features layer
The land lot represented by whites have the highest suitability to build quarantine building as it have the furthest distance (929.26m) away from the natural attractions. When the color change from whites to a darker color it means the distance is getting nearer to the natural attractions until it reaches to 0m which is represented by blacks (refer to figure 2.1). However, the requirement for natural is different from factors like economic and accessibility. For natural conversation factor, the selected site should be away from forested land, park and water. Therefore, in order to standardize across all 4 different factors, I have to inverse natural conversation factor first(1/proximity map of natural), so that it comes to a common agreement that those areas nearer to natural conversation, residence area, road and flat ground would be represented by whites and when the distance or slope degree increases the color also change to a darker color. After inversing the natural conversation factor, the minimum number is 0.00107612 and the maximum number is 0.2.
the study area and Proxmity to building layer
The land lots represented by whites have the highest suitability to build quarantine building as it has the furthest distance (890.183m) away from the housing areas or offices. When the color changes from whites to a darker color it means that the distance is getting nearer to residential areas until it reaches 0m which is represented by blacks (refer to figure 2.2). However, due to health risk factor, the idea location for quarantine building would be build at those land lots represented by white or if not, a lighter color would be preferred. For building, it applies the same concept as natural as it mentioned in the task that the selected site should be away from population i.e. housing areas and offices in order to avoid disease spreading to the nearby population. Therefore, inverse health risk factor (1/proximity map of building) would be required. After inverse the health risk factor, the minimum number is 0.00112337 and the maximum number is 0.2.
the study area and slope layer
The economic factor is based on slope and it is derived from proximity to elevation, those land lots represented by blacks have a flatter ground of 0 degree and land lots represented by whites with elevated ground of 36.664 degree. Both left and right-hand side of the study area tend to have a flatter ground compared to area in the center of the study area. From the slope layer we can infer that the center of the study area might not be an ideal location to build quarantine building as it stated in the task that the selected site should avoid steep slope. This is because construction at steep slope tends to involve a lot of cut-and-fill and will lend to relatively higher development cost.
