Methodology

In summary, our group created a network analysis near every station by setting 10 and 15 minutes buffer distances and Iso-Areas Polygons. On average, a person could cover about one mile (1.6km) in 20 minutes. We used 10 and 15 minutes as a maximum span of time that a person is willing to cover to walk to an MRT Station from his or her home, which would equate to about 0.8 and 1.2km respectively. The resulting layers will be used for our analysis of the MRT stations’ catchment areas.

Data Preparation and Cleaning

Selection of Required Data

The Datasets that are being used for the project includes:

Adding of Datasets

  • TE Stage 4 MRT Stations

    • First go to ‘Add Layer’, then ‘Add Delimited Text Layer’.

    • Select the TE Stage 4 MRT Stations.csv CSV file. Under the X and Y field, select Longitude and Latitude respectively. Leave Geometry CRS as WGS 84.

    • The following points should appear as below.

    • Save the layer as GeoPackage and name the layer Stage4_TE_Line, and the CRS as EPSG:3414 – SVY21.

  • MP19 Subzone Layer

    • Add in the MP19 Subzone kml layer.

  • OSM layer

    • Add the OSM road layer in. Use ‘Select by polygon’ and select the area outlined by the MP19 Subzone layer, leaving out some of the SOuthern Islands, Pulau Ubin and Pulau Tekong.

    • Export and Save Selected Features as GeoPackage. Name the layer as all_roads.

    • Repeat the steps for OSM buildings layer and name it as all_buildings.

    • Remove the OSM buildigns and roads layer.

  • Other MRT lines

    • Add the MRTLRTStnPtt.shp file into the layers. There are many different lines but the ones closest to the Stage 4 Thomson-East Coast Line are Circle Line, Downtown Line, and the East-West Line.

    • Open the attribute table of the shape file and click ‘Select by Expression’.

    • Select by STN_NO with the letter ‘CC’ in it.

    • Save the selected features and name the layer Circle Line.

    • Do the same for the Downtown and East-West Line, replacing the ‘CC%’ with ‘DT%’ and ‘EW%’ and name the layers Downtown Line and East-West Line respectively.

  • Cleaning Road Data

    • There are expressways where the people are not able to walk on. Thus, we have to filter out the following roads with these fclass: motorway, motorway_link, trunk, trunk_link.

    • Select all_roads layer and open attribute table, click on select by expression.

    • Select the roads with fclass: ‘motorway’, ‘motorway_link’, ‘trunk’, ‘trunk_link’.

    • Select ‘Invert Selection’ to select all the roads without the ones needed to be filtered away. Export and save selected features in GeoPackage and name the layer as walking_roads.

  • Cleaning Buildings Data

    • The all_buildings layer consists of several null values under the “type” column. After looking at Google Maps, there consists of different types of low-rise buildings, shophouses, etc. Thus, the team decided to replace the null values for “type” column with low-rise buildings.

    • Right-click on all_buildings layer and select Open Attribute Table. Click on Select by Expression. Type in “type” is null in the expression box. Click on Select Features. This will select all building types that have null values.

    • After selecting features, Open field calculator and update the values to ‘low-rise buildings’.

    • Click on the pencil icon to save the edits.

Preparation of Buffers and Iso-Area Polygons

Objective: Creation of Buffer and Iso-Areas with these data

  • Creating a 15min Buffer Area

    • Select the first station of Stage 4 Thomson-East Coast Line (Founders’ Memorial).

    • Go to Vector –> Select Geoprocessing Tools –> Buffer.

    • Check ‘Selected Features only’

      Distance – 0.75 miles (average walking distance of 15min)

      Segments – 100

    • If done correctly, this should be shown:

    • Save the temporary layer ‘Buffer’ that was generated to GeoPackage, with the layer name as TE22A 15mins Walking Radius.

  • Creating a 10min Buffer Area

    • Using the same steps, the only difference is changing the distance to 0.5miles (average walking distance of 10mins).

    • If done correctly, this should be shown:

  • Creating a 15min Iso-Area as Polygon

    • Using a plugin, QNEAT3, under Iso-Areas, select Iso-Area as Polygons (from Layer).

    • Under Vector layer, select walking_roads layer.

      Under Start Points, select Stage4_TE_line, check selected features only Change Unique point ID Field to STN_NAME.

      Under Size of Iso-Area and Contour Interval, input 900 (15 mins = 900 seconds).

      Change path type to calculate to Fastest Path (time optimisation).

    • If done correctly, this should be shown:

    • Save the polygon layer into the GeoPackage, naming the layer and remove the interpolation layer.

  • Creating a 10min Iso-Area as Polygon

    • Using the same steps, the only changes that needs to be made is:

      Under Size of Iso-Area and Contour Interval, input 600 (10 mins = 600 seconds).

    • If done correctly, this should be shown:

  • Catchment area Buildings – We will be looking at what buildings are there in the catchment area.

    • For 15min Catchment Area, select Clip under Geoprocessing Tools.

    • Under Input Layer, select all_buildings layer

      Under Overlay layer, select TE22A 15mins Catchment Area layer

    • If done correctly, the following temporary ‘Clipped’ should appear and look like this:

    • Save the ‘Clipped’ temporary layer as TE22A 15mins Buildings to the GeoPackage.

    • For 10min Catchment Area, repeat the same steps but replacing the Overlay layer with TE22A 10mins Catchment Area, and save to GeoPackage as TE22A 10mins Buildings.

    • If done correctly, this should be shown: (With the 10mins layer active only)

  • Repeat the Steps for Buffer, Iso-Area Polygon and Catchment area buildings for the rest of the Stage 4 Thomson-East Coast Line.

Creating Symbols and /or Area Colour

  • For point Data (Symbols)

    • We will need to use symbols to represent the various point layers for easier visualisation.

    • Firstly, we will save each station individually into the GeoPackage.

    • Using TE22A station, select the feature and Save Selected Feature as GeoPackage. Name the layer Founders’ Memorial MRT.

    • Right Click on Layer –> click on Properties. A pop up ‘Layer Properties’ will appear.

    • Click on Symbology –> Simple Marker –> Change the Symbol layer type to SVG Marker –> Search for ‘train’ at the search bar under SVG images –> double-click on the icon

    • Repeat the steps above for the other Stage 4 Thomson-East Coast Line stations.

    • For Circle Line, Downtown Line and East-West Line, without the need to save each station individually, repeat the above steps but with the following colours:

      Circle Line – #ffbf00

      Downtown Line – #0009be

      East-West Line – #00d644

    • If done correctly, this should be shown:

  • For Buffer Layer

    • We will be using a standardised colour across all 10min and 15min Buffer Layers. In addition, the transparency will be lower for clearer visibility of the catchment area.

    • Using TE22A 15mins Walking Radius, right click on select Properties. Click on Symbology –> Change fill colour to #000080 –> Change Opacity to 30% –> Save Symbol and name it as a Buffer layer –> it should appear in Project Styles for east access.

    • If done correctly, this should be shown:

    • Repeat the steps for all 10min and 15min Walking Radius (Use the Saved Symbol in Project styles for easy access).

    • If done correctly, this should be shown:

  • For Iso-Area Polygon

    • Using TE22A 15mins Catchment Area, right click and select Properties –> Click on Symbology –> Change fill colour to #ffdf53 –> Change Opacity to 70% –> Save Symbol and name it as Iso-Area layer –> it should appear in Project Styles for easy access.

    • If done correctly, this should be shown:

    • Repeat the steps while using the Iso-Area in Project styles for the rest of the 10mins and 15mins Catchment Area.

    • If done correctly, this should be shown:

  • For the buildings in Catchment Area

    • We will categorise the buildings based on its attribute ‘type’. We will also be standardising each colour for each type based on the following colours:

      Building Type Colour Code
      apartments #477bce
      church #e1de21
      commercial #beb956
      construction #45e1c4
      garage #6c6c6c
      house #9cf046
      kindergarten #a27a50
      low-rise building #0101ff
      mosque #55b987
      public #42ce81
      residential #4a2b84
      roof #ea58ca
      school #ff3355
      temple #c3154c
      terrace #6c8341
      retail #9200f4
      hut #501dcf
      office #ff85ed
      EiS-Residences #01f7ff
      service #d44f3b

    • Using TE22A 15mins Building Layer, Right Click and Select Properties –> Select Symbology –> save the symbols for the type of buildings. Below is an example for apartments:

    • Do the same for the other categories of buildings.

    • If done correctly, this should show in your Project Styles:

    • With the saved symbols, now select categorised symbols in the drop-down box at the top –> Under Value, select ‘type’ –> Click Classify –> Change the colours according to the saved symbols –> remove all other values.

    • Repeat the steps for all the stations’ catchment area buildings.

    • If done correctly, this should show:

  • Thickness of roads

    • For ease of visibility, we will decrease the walking_roads layer thickness to 0.2mm and change the colour to black.

Piecing the layers together

  • After we have completed the standardisation and changing of the symbology and colours, we will now piece the layers together. Our analysis will be based on each Catchment Area based on 10mins or 15mins walking time.

    • Using TE22A 15mins, activate and place the layers in the following order: the MRT stations and lines, walking_roads, TE22A 15mins Buildings, TE22A 15mins Catchment Area, TE22A 15mins Walking Radius, and Open Street Map, as show in the Layers Panel in the image below:

    • Right click on the Walking radius and click Zoom to Layer. Create a new Print Layout –> Add Map and Legends –> Save as Image.

    • If done correctly, it should look similar to the screenshot below:

    • Repeat the above steps for each station’s 10mins and 15mins layers as our analysis will be based on each station’s 10mins and 15mins Catchment Areas.