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Shape files of Europe maps are available on the Eurostat website. I downloaded NUTS_2013_60M_SH. The tool (readOGR from the R package Rgdal) I use to load the map shows the following proj4string:

 "+proj=longlat +ellps=GRS80 +no_defs"

Metadata provided with these files doesn't contain an EPSG code for the projection. I would like to use such a code to define the projection when I load the map.

A search for RS80 on the spatial reference site returns several code pages and none seem to be relevant.

What is the EPSG code of the projection used in these Eurostat maps?

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Looking on https://epsg.io, the only result containing GRS80 is EPSG:42310, which is a Mercator projection, thus not compatible with +proj=longlat". This confirms the results of your search on http://spatialreference.org/.

For this reason, I don't think there is an EPSG code for this projection, which is not surprising given that GRS80 is a fairly outdated CRS (it was soon replaced by the famous WGS84).

EDIT: I tried to load the same file in QGIS, which automatically detected the CRS as EPSG:4258 (which is actually longlat ETRS89). The full description is +proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs.

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    The site doesn't find any other GRS80 references because GRS80 is an ellipsoid and not usually used in the name of a coordinate reference system. – mkennedy Feb 26 '16 at 18:12
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It seems there is no point here to try to deduce the EPSG code from R: it's already hidden in the delivered downloaded data.

How can I say this?

  • download the NUTS-2013-60M-SH.zip file
  • unzip it
  • find a file NUTS_2013_60M_SH/data/NUTS_RG_60M_2013.shp.xml. A file with a shp.xml extension is a metadata file associated with each data set produced when you use ArcGIS (I use QGIS but I know this)
  • search for a string "EPSG"
  • find near a code 4258 (excerpt below indented) ... <refSysInfo> <RefSystem> <refSysID> <idCodeSpace Sync="TRUE">EPSG</idCodeSpace> <idVersion Sync="TRUE">8.2.6</idVersion> <identCode code="4258" Sync="TRUE" value="4258"/> </refSysID> </RefSystem> </refSysInfo> ...
  • go to https://epsg.io
  • search for EPSG 4258
  • confirm the extent is Europe http://epsg.io/4258
  • see technical detail about the projection at http://etrs89.ensg.ign.fr/

You can also look at NUTS_2013_60M_SH/data/NUTS_RG_60M_2013.prj: it contains an ESRI WKT string definition for the projection that match the one available at http://epsg.io/4258

  • The point of my question was that eurostat's shp.xml file didn't contain an EPSG code. – Paul Rougieux Feb 29 '16 at 10:40
  • NUTS_RG_60M_2013.prj did contain a description of the datum GCS_ETRS_1989. – Paul Rougieux Feb 29 '16 at 10:47
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    See my answer edited. The EPSG code is here but not the projection string corresponding to it. – ThomasG77 Feb 29 '16 at 10:57
  • Both EPSG code and projection string were quite hard to find. I have a better idea of the structure of these .shp.xml and .prj files now. – Paul Rougieux Feb 29 '16 at 14:48

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