In-Class Excercise 5

Published

February 8, 2023

Getting Started

# sfdep (gonna use for the take home excercise 2)
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:\mayurims\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

# Use EPSG to find the projection of a country. For instance, Taiwan is EPSG:3829
stores <- st_read(dsn = "data",
                  layer = "stores") %>%
  st_transform(crs = 3829)

Reading layer `stores' from data source 
  `C:\mayurims\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

Visualizing the sf layers

tmap_mode("view")
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)

# This is required for Take Home Excercise 3
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 is a datable. You dont have a unique identifier.
LCLQ <- local_colocation(A, B, nb, wt, 49)

# The cbind only works if your dont sort the results (LCLQ). 
LCLQ_stores <- cbind(stores, LCLQ)

tmap_mode("view")
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))