I am trying to create a world shape file similar to London one. I am using this shape file. Link to the shape file. I have downloaded this file and I issue the command lnd@countries. I am getting the following error. Any suggestions?
library(rgdal)
lnd <- readOGR(dsn = "countries", layer = "ne_10m_admin_0_countries")
head(lnd@countries, n = 4)
Error in head(lnd@countries) :
no slot of name "countries" for this object of class "SpatialPolygonsDataFrame"
You are mistaking the syntax... An OGR data object will have the data stored in myobject@data, and the coordinates in myobject@coords.
data = readOGR("/Users/Benjamin/Desktop/ne_10m_admin_0_countries/ne_10m_admin_0_countries.shp", "ne_10m_admin_0_countries")
colnames(data@data)
Note that there is no field named "countries", which is what you are asking for in your question:
[1] "scalerank" "featurecla" "LABELRANK" "SOVEREIGNT" "SOV_A3" "ADM0_DIF" "LEVEL" "TYPE" "ADMIN" "ADM0_A3" "GEOU_DIF"
[12] "GEOUNIT" "GU_A3" "SU_DIF" "SUBUNIT" "SU_A3" "BRK_DIFF" "NAME" "NAME_LONG" "BRK_A3" "BRK_NAME" "BRK_GROUP"
[23] "ABBREV" "POSTAL" "FORMAL_EN" "FORMAL_FR" "NOTE_ADM0" "NOTE_BRK" "NAME_SORT" "NAME_ALT" "MAPCOLOR7" "MAPCOLOR8" "MAPCOLOR9"
[34] "MAPCOLOR13" "POP_EST" "GDP_MD_EST" "POP_YEAR" "LASTCENSUS" "GDP_YEAR" "ECONOMY" "INCOME_GRP" "WIKIPEDIA" "FIPS_10_" "ISO_A2"
[45] "ISO_A3" "ISO_N3" "UN_A3" "WB_A2" "WB_A3" "WOE_ID" "WOE_ID_EH" "WOE_NOTE" "ADM0_A3_IS" "ADM0_A3_US" "ADM0_A3_UN"
[56] "ADM0_A3_WB" "CONTINENT" "REGION_UN" "SUBREGION" "REGION_WB" "NAME_LEN" "LONG_LEN" "ABBREV_LEN" "TINY" "HOMEPART"
To get the first four countries by name, noting that this depends on the order of features not the alphabetic order (which happens to match here):
head(data@data$NAME, 4)
Note that they were clever enough to include a NAME_SORT field for proper ordering (in English, presumably).