In-class Exercise 5

Getting Started

pacman:: p_load(tidyverse,tmap,sf,sfdep)

Importing Data

studyArea <- st_read(dsn="data",
                     layer="study_area") %>%
  st_transform(crs=3829)

Reading layer `study_area' from data source 
  `C:\G2wongkelly\IS415_GAA\In_Class_Ex\In_Class_Ex05\data' using driver `ESRI Shapefile'
Simple feature collection with 7 features and 7 fields
Geometry type: POLYGON
Dimension:     XY
Bounding box:  xmin: 121.4836 ymin: 25.00776 xmax: 121.592 ymax: 25.09288
Geodetic CRS:  TWD97

stores <- st_read(dsn="data",
                     layer="stores") %>%
  st_transform(crs=3829)

Reading layer `stores' from data source 
  `C:\G2wongkelly\IS415_GAA\In_Class_Ex\In_Class_Ex05\data' using driver `ESRI Shapefile'
Simple feature collection with 1409 features and 4 fields
Geometry type: POINT
Dimension:     XY
Bounding box:  xmin: 121.4902 ymin: 25.01257 xmax: 121.5874 ymax: 25.08557
Geodetic CRS:  TWD97

Visualising the sf layers

tmap_mode("view") 

tmap mode set to interactive viewing

tm_shape(studyArea) + 
  tm_polygons() +
tm_shape(stores)+ 
  tm_dots(col = "Name", 
          size = 0.01,
          border.col = "black", 
          border.lwd = 0.5) +
  tm_view(set.zoom.limits = c(12,16))

Local Colocation Quotients (LCLQ)

nb <- include_self(
  st_knn(st_geometry(stores),6))

wt <- st_kernel_weights(nb,
                     stores,
                     "gaussian",
                     adaptive = TRUE)

FamilyMart <- stores %>%
  filter(Name == "Family Mart")
A <- FamilyMart$Name

SevenEleven <- stores %>%
  filter(Name == "7-Eleven")
B <- SevenEleven$Name

LCLQ <- local_colocation(A,B,nb,wt,49)

LCLQ_stores <- cbind(stores, LCLQ)

tmap_mode("view")

tmap mode set to interactive viewing

tm_shape(studyArea) + 
  tm_polygons() + 
  tm_shape(LCLQ_stores)+
    tm_dots(col = "X7.Eleven",
            size = 0.01,
            border.col = "black",
            border.lwd = 0.5) + 
  tm_view(set.zoom.limits = c(12,16))