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rrasterspatial

Subsetted states look very weird with function raster::getData

I used raster::getData to obtain a Large SpatialPolygonsDataFrame details below

states <- raster::getData("GADM", country = "United States", level = 1

I subsetted IL and WI...

statesilwi <- states[states$NAME_1 == "Illinois" | states$NAME_1 == "Wisconsin",]

But when I plot it, it Illinois looks a little bit funky, why is this happening and is there a way to fix it?

plot(statesilwi)

enter image description here

Solution

  • "looks a bit funky" is not very clear. But it seems to me that @rawr is correct. A part of Lake Michigan belongs to Illinois.

    You can remove Lake Michigan like this:

    library(terra)
library(geodata)
us <- geodata::gadm("United States", level = 2, path=".")
us <- us[us$TYPE_2 != "Water body", ]
s <- us[us$NAME_1 %in% c("Illinois", "Wisconsin"),]
s <- aggregate(s, "NAME_1")
plot(s)