In-class Exercise 1

1. Getting Started

1.1 Install and launching R packages

The code chunk below load the following packages:

• tmap : for thematic mapping

• sf : for geospatial data handling

• tidyverse: for non-spatial data handling

pacman::p_load(tmap, sf, tidyverse)

1.2 Importing the OD data

Firstly, we will import the Passenger Volume by Origin Destination Bus Stops data set downloaded from LTA DataMall by using read_csv() of readr package.

odbus <- read_csv("data/origin_destination_bus_202308.csv")

A quick check of odbus tibble data frame shows that the value in ORIGIN_PT_CODE.

odbus$ORIGIN_PT_CODE <- as.factor(odbus$ORIGIN_PT_CODE)

odbus$DESTINATION_PT_CODE <- as.factor(odbus$DESTINATION_PT_CODE)

1.3 Extracting the study data

For the purpose of this exercise, we will extract commuting flows on weekday between 7 to 9 o’clock.

origtrip_7_9 <- odbus %>%
  filter(DAY_TYPE == "WEEKDAY") %>%
  filter(TIME_PER_HOUR >= 7 &
           TIME_PER_HOUR <= 9 ) %>%
  group_by(ORIGIN_PT_CODE) %>%
  summarise(TRIPS = sum(TOTAL_TRIPS)) %>%
  ungroup()

Two geospatial data will be used in this exercise, they are:

busstop <- st_read(dsn = 'data', layer = 'BusStop') %>%
  st_transform(crs= 3414)

mpsz <- st_read(dsn = 'data', layer = 'MPSZ-2019') %>%
  st_transform(crs= 3414)

Reading layer `MPSZ-2019' from data source 
  `/Users/smu/Rworkshop/jiawenoh/ISSS624/In-class_Ex/In-class_Ex01/data' 
  using driver `ESRI Shapefile'
Simple feature collection with 332 features and 6 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: 103.6057 ymin: 1.158699 xmax: 104.0885 ymax: 1.470775
Geodetic CRS:  WGS 84

mpsz

Simple feature collection with 332 features and 6 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: 2667.538 ymin: 15748.72 xmax: 56396.44 ymax: 50256.33
Projected CRS: SVY21 / Singapore TM
First 10 features:
                 SUBZONE_N SUBZONE_C       PLN_AREA_N PLN_AREA_C       REGION_N
1              MARINA EAST    MESZ01      MARINA EAST         ME CENTRAL REGION
2         INSTITUTION HILL    RVSZ05     RIVER VALLEY         RV CENTRAL REGION
3           ROBERTSON QUAY    SRSZ01  SINGAPORE RIVER         SR CENTRAL REGION
4  JURONG ISLAND AND BUKOM    WISZ01  WESTERN ISLANDS         WI    WEST REGION
5             FORT CANNING    MUSZ02           MUSEUM         MU CENTRAL REGION
6         MARINA EAST (MP)    MPSZ05    MARINE PARADE         MP CENTRAL REGION
7                   SUDONG    WISZ03  WESTERN ISLANDS         WI    WEST REGION
8                  SEMAKAU    WISZ02  WESTERN ISLANDS         WI    WEST REGION
9           SOUTHERN GROUP    SISZ02 SOUTHERN ISLANDS         SI CENTRAL REGION
10                 SENTOSA    SISZ01 SOUTHERN ISLANDS         SI CENTRAL REGION
   REGION_C                       geometry
1        CR MULTIPOLYGON (((33222.98 29...
2        CR MULTIPOLYGON (((28481.45 30...
3        CR MULTIPOLYGON (((28087.34 30...
4        WR MULTIPOLYGON (((14557.7 304...
5        CR MULTIPOLYGON (((29542.53 31...
6        CR MULTIPOLYGON (((35279.55 30...
7        WR MULTIPOLYGON (((15772.59 21...
8        WR MULTIPOLYGON (((19843.41 21...
9        CR MULTIPOLYGON (((30870.53 22...
10       CR MULTIPOLYGON (((26879.04 26...