GIS-in-R--GeoTaiwan
GIS is used to develop and store geographic and attribute data. Geographic analysis which looks at spatial distributions of lands, people and resources and attempts to explain and predict.
Setup
x <- c("ggmap", "rgdal", "rgeos", "maptools", "dplyr", "tidyr", "tmap")
lapply(x, library, character.only = TRUE)Load data
GIS datasets
twn <- readOGR(dsn = "C:/Users/USER/Desktop/Spatial task/TWN_adm/TWN_adm2.shp")## OGR data source with driver: ESRI Shapefile
## Source: "C:\Users\USER\Desktop\Spatial task\TWN_adm\TWN_adm2.shp", layer: "TWN_adm2"
## with 22 features
## It has 11 fields
## Integer64 fields read as strings: ID_0 ID_1 ID_2
Plotting Taiwan!
plot(twn)
Checking the centre of Taiwan
twnE <- coordinates(gCentroid(twn))[[1]]
twnN <- coordinates(gCentroid(twn))[[2]]
twnE ; twnN## [1] 120.9682
## [1] 23.74749
east <- sapply(coordinates(twn)[,1], function(x) x > twnE)
north <- sapply(coordinates(twn)[,2], function(x) x > twnN)Select zones where
names(twn)## [1] "ID_0" "ISO" "NAME_0" "ID_1" "NAME_1"
## [6] "ID_2" "NAME_2" "TYPE_2" "ENGTYPE_2" "NL_NAME_2"
## [11] "VARNAME_2"
unique(twn$ID_0)## [1] 225
## Levels: 225
unique(twn$ID_1)## [1] 1 2 3 4
## Levels: 1 2 3 4
unique(twn$ID_2)## [1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
## Levels: 1 10 11 12 13 14 15 16 17 18 19 2 20 21 22 3 4 5 6 7 8 9
unique(twn$NAME_0)## [1] Taiwan
## Levels: Taiwan
unique(twn$NAME_1)## [1] Kaohsiung Pratas Islands Taipei Taiwan
## Levels: Kaohsiung Pratas Islands Taipei Taiwan
unique(twn$NAME_2)## [1] Kaohsiung City <NA> Taipei City Changhwa
## [5] Chiayi Hsinchu Hualien Ilan
## [9] Kaohsiung Keelung City Miaoli Nantou
## [13] Penghu Pingtung Taichung City Taichung
## [17] Tainan City Tainan Taipei Taitung
## [21] Taoyuan Yunlin
## 21 Levels: Changhwa Chiayi Hsinchu Hualien Ilan ... Yunlin
unique(twn$TYPE_2)## [1] Chuan-shih <NA> District|Hsien Shi
## Levels: Chuan-shih District|Hsien Shi
unique(twn$ENGTYPE_2)## [1] Special Municipality <NA> County
## [4] Municipality
## Levels: County Municipality Special Municipality
unique(twn$NL_NAME_2)## [1] <NA>
## Levels:
unique(twn$VARNAME_2)## [1] Gaoxiong Shi <NA>
## [3] Taibei Shi Zhanghua|Changhua
## [5] Jiayi|Chiai Xinzhu
## [7] Hualia Yilan
## [9] Gaoxiong Jilong Shi|Chilung City
## [11] Pingdong Taizhong Shi
## [13] Taizhong Tainan Shi
## [15] Taibei Taidong
## [17] Yüanlin
## 16 Levels: Gaoxiong Gaoxiong Shi Hualia ... Zhanghua|Changhua
plot(twn)
plot(twn[twn$ID_2 == 2, ], add = TRUE, col = 'Red')
a <- is.na(twn$NAME_2)
twn$NAME_2[!a]## [1] Kaohsiung City Taipei City Changhwa Chiayi
## [5] Hsinchu Hualien Ilan Kaohsiung
## [9] Keelung City Miaoli Nantou Penghu
## [13] Pingtung Taichung City Taichung Tainan City
## [17] Tainan Taipei Taitung Taoyuan
## [21] Yunlin
## 21 Levels: Changhwa Chiayi Hsinchu Hualien Ilan ... Yunlin