You can probably use CRS("+proj=longlat +datum=WGS84")

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>Hello,
>I?m trying to use the map function from package maps to draw the
contiguous United States with the projection, "+proj=aea >+lat_1=29.5
+lat_2=45.5 +lat_0=39.8 +lon_0=-98.6 +x_0=0 +y_0=0 +datum=WGS84 +units=km
+no_defs".
>Below is my code I have written, but I don't know what to put for X. The
maps documentation says, "the default is to use a >rectangular projection
with the aspect ratio chosen so that longitude and latitude scales are
equivalent at the center of the >picture." I can't figure out how to
specify this in terms of a CRS string for X.
>us = map("state", plot=FALSE, fill=TRUE, col="transparent")
>us_sp = map2SpatialPolygons(us, IDs=us$names, proj4string = CRS(X) )
#don't know what to put for X
>proj.string.alb = CRS("+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=39.8
+lon_0=-98.6 +x_0=0 +y_0=0 +datum=WGS84 >+units=km +no_defs")
>us_sp = spTransform(us_sp, CRS=proj.string.alb)
>plot(us_sp)
>Thanks for your help!

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