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rr-sprgdaltmapproj

sp::proj4string(obj) : CRS object has comment, which is lost in output in R

I am trying to plot a map using tmap library:

library("rgdal")
library("tmap")
area_dnipro <- readOGR("dnipro.shp", encoding = "UTF-8", use_iconv=TRUE)
tm_shape(area_dnipro) + tm_polygons()

But during plotting I am getting this message:

Warning message:
In sp::proj4string(obj) : CRS object has comment, which is lost in output

Can anybody clearly explain the meaning of this message? Why does library (I guess sp) outputs this for me? Something wrong with my shp-file? Can I do something in order not to get this warning? - May be transform my shape-file somehow? Because I am plotting this map from RStudio to HTML and don't want this text in the resulting HTML:

tmap plot

Here are my shape-files: download

P.S. I am aware about this topic but it doesn't shed light on this problem (at least for me). I don't understand what is the problem and what to do.

Solution

  • Use the sf package to read the shapefile:

    R> area_dnipro <- sf::read_sf("dnipro.shp")
R> tm_shape(area_dnipro) + tm_polygons()

    this does not show the warning.

    See also ?tm_shape:

    shp: shape object, which is an object from a class defined by the ‘sf’ or ‘stars’ package. Objects from the packages ‘sp’ and ‘raster’ are also supported, but discouraged.