SMT201 AY2019-20G1 EX2 Kok Su Yee

Take Home Exercise 2- GIS Modelling for Urban Land Suitability Study

Task: Identify a location suitable for building a national Communicable Disease Quarantine Centre at the selected site of Gombak Planning Subzone

Part 1: Gombak Study Area Map layout with four views

In order to determine whether the location is suitable to build a national Communicable Disease Quarantine Centre, there are a few critical decision factors to take into consideration: Economic, Accessibility, Health Risk and Natural Conservation. Since the selected site is at Gombak Planning Subzone, the following is the map layout that consists of views in relation to the decision factors.

Accessibility Factor: Gombak Study area and the target roads

The target road types are service roads and tracks and the selected site has to be close to the existing local roads. Looking at the first view of the map, we can see that there is high accessibility of service road lines in the North and East side of the Gombak Subzone whereas the other parts of the Gombak does not have local roads to access. To ensure that there is no difficulty in transporting the building materials during the construction stage, the quarantine centre can be built in North eastern area of Gombak.

Health Risk Factor: Gombak Study area and buildings

Health risk factor plays a part when selecting the right location to build the quarantine centre so that it is at far proximity from the buildings that are populated with people. Considering this critical factor, it would be appropriate to build the quarantine centre at the Southern side of Gombak as there is no presence of buildings. The overall presence of the buildings is widely spread out at the Northen and Western part of Gombak so there are other available lands for us to select from.

Natural Conservation Factor: Gombak Study area and the target natural features

From this map view, it is apparent that there is not many natural features, namely forested land, park and water in Gombak Subzone. The natural conservation factor will not contribute a lot to selecting the suitable site. The natural feature types are represented by their own nature colours, green and blue in the map. In this case, there are available land at the Southern and Eastern areas of Gombak where there is no sight of natural features and it will be appropriate to construct the quarantine centre there.

Economic Factor: Gombak Study area and digital elevation

The selected site has to meet the economic factor where there is no steep slope in the vicinity and this to avoid incurring high development cost due to cut-and-fill activities. In this map view of digital elevation raster map, the highest value of elevation is 143 metres above the sea level. The highly elevated area is situated around Southern side of Gombak Subzone where it is coloured in white in that part and this area is suitable for building the quarantine centre.

Part 2: Proximity Map layout with four views

Proximity analysis is essential for us to define the best site location, it measures the distance between study area to the different factors layers. As a result, proximity maps are created to display the relations of the study area, Gombak Subzone in proximity with the different factors layers.

Accessibility Factor: Study area and proximity to target roads layer

With the rasterised road layer to shows the proximity of the targets road to Gombak, it is clear that the minimum and maximum distance from the road are 0 and 743.303 metres respectively.

Health Risk Factor: Study area and proximity to buildings layer

With the rasterised road layer to shows the proximity of the buildings to Gombak, it is clear that the minimum and maximum distance from the road are 0 and 838.446 metres respectively.

Natural Conservation Factor: Study area and proximity to target natural features layers

With the rasterised road layer to shows the proximity of the target natural features to Gombak, it is clear that the minimum and maximum distance from the road are 0 and 863.669 metres respectively.

Economic Factor: Study area and slope layer

The lowest degree for the slope layer is 0 and the highest degree is 36.419 degrees. The grids that has a darker grey intensity displays the locations with relatively gentle slope. Locations with steeper slope are indicated with lighter grey grids.

Part 3: Map layout with four views showing the criterion scores of each factor layers

The scale of measurement of the different factors layers proximity are currently different. Therefore, I uses the method of Min-Max criteria standardization techniques (𝑴𝑴(𝒙𝒊𝒋)=𝒙𝒊𝒋−𝒙𝒎𝒊𝒏𝒙𝒎𝒂𝒙−𝒙𝒎𝒊𝒏) to standardise all the factors and the criterion scores are calculated with the application of Raster Calculator in QGIS:

• Economic factor
• Accessibility factor
• Health risk factor
• Natural conservation factor

After setting up the various criterion scores, the map layout displaying the four views of these criterion scores is created:

• Economic factor
  

The standardised score would mean that the higher the score, the degree of slope will get steeper. Hence, it would not be good to build the quarantine centre at the area marked as red colour where the score is high and it will involve a lot of cut-and-fill.

• Accessibility factor
  

The higher the accessibility criterion score, the more suitable the land is to build the quarantine centre. Thus, the areas that are marked as blue are suitable to be selected since there are local road access for transporting the building materials.

• Health risk factor
  

The higher the health risks criterion score, the less suitable the land is to build the quarantine centre. The areas that are indicated as red are not suitable to be selected.

• Natural conservation factor
  

The higher the natural conservation criterion score, it means that the environment is highly surrounded by the forested land, parks and water. The chosen land for the quarantine centre should fall in the area marked as blue.

Part 4: Analytical Hierarchical Process Input Matrix and Result Report

There are multiple objectives present and the requirement to fulfill the decision factors in choosing the most suitable land for the quarantine centre. I have computed a AHP (Analytical Hierarchical Process) Table which serve as a decision making tool in justifying the results from the factors and ensure the result produced is consistent. The AHP template is adopted from the Excel-based AHP library provided by SCB Associates.

References

• Data Gov Master Plan 2014 Subzone Boundary " Master Plan 2014 Subzone Boundary"
  
• OpenStreetMap (OSM) Data sets " OpenStreetMap (OSM) Data sets"
  
• ASTER Global Digital Elevation Model (GDEM) Dataset "ASTER Global Digital Elevation Model (GDEM) Dataset"