空間分析　 實習五

助教 杜承軒 2021.04.25

台南市學校的空間型態檢定

library(sf)
school=st_read("D:/1092SA/Data/Schools.shp")

#1. Fishnet
grid = st_make_grid(school, 5000) %>% st_sf

#2. Quadart Count
count = st_contains(grid, school) %>% lengths
k = length(count)

#3. VMR
VMR   = var(count)/mean(count)
VMR.se= sqrt(2/(k-1))
VMR.t = (VMR-1)/VMR.se

設定顯著水準 \(\alpha=0.05\)
\(H_0\)：點分布為隨機分布\((s^2=\lambda , VMR=1)\)
\(H_a\)：點分布非隨機分布\((s^2\neq\lambda , VMR\neq1)\)

VMR.p = 2*pt(VMR.t,k-1,lower.tail=VMR.t<0)
VMR.p < 0.05

[1] TRUE

\(p-value<\alpha\)，拒絕假設檢定，台南市學校點分布非隨機分布。

---

library(tmap)
grid$count=count
qtm(grid,fill="count")+qtm(school)