Hi Romina, looking at { http://spatialreference.org/ref/epsg/32721/ } I can see the UTM zone 21H or also 21S for South spans longitudes in the range (-80,-60) so I guess you just inverted easting and northing in your code:
So: $ LatLong <- data.frame(Y=-35.14189, X=-57.39206) # <-- X is the LONGITUDE. $ coordinates(LatLong) <- ~ X+Y $ proj4string(LatLong) <- CRS("+init=epsg:4326") $ Utm <- spTransform(LatLong, CRS("+init=epsg:32721")) $ Utm SpatialPoints: X Y [1,] 464285.6 6111151 Cheers, Piero In general anyway, it's safer to identify CRS by EPSG code -- which in your case is 32721 (http://spatialreference.org/ref/epsg/32721/) --, then you can create it like this: $ Utm <- spTransform(LatLong, CRS("+init=epsg:32721")) On 6 June 2012 17:57, <rscardamag...@ege.fcen.uba.ar> wrote: > Hello, > I need some help transforming Latitude Longitude coordinates (in decimal > degrees) to UTM (zone 21 H, since Im in Buenos Aires, Argentina). > This is the script I used. The transformation for the easting coordinates > is correct but not for the Northing. > > > LatLong <- data.frame(X = coordenadas2[,1], Y = coordenadas2[,2]) > > LatLong > X Y > 1 -35.14189 -57.39206 > 2 -35.14072 -57.39421 > 3 -35.14507 -57.38274 > 4 -35.14390 -57.39083 > 5 -35.14496 -57.39312 > 6 -35.14069 -57.39280 > 7 -35.14241 -57.39119 > > > coordinates(LatLong) <- ~ Y + X > > proj4string(LatLong) <- CRS("+proj=longlat +ellps=WGS84 +datum=WGS84") > > Utm <- spTransform(LatLong, CRS("+proj=utm +zone=21 ellps=WGS84")) > > Utm > > SpatialPoints: > Y X > [1,] 464285.6 -3888849 > [2,] 464089.3 -3888720 > [3,] 465136.0 -3889198 > [4,] 464398.6 -3889071 > [5,] 464190.4 -3889189 > [6,] 464217.7 -3888716 > [7,] 464365.1 -3888906 > > Coordinate Reference System (CRS) arguments: +proj=utm +zone=21 > +ellps=WGS84 > > It seems the Easting coordinates are well transformed, but the Northing > should be around 6111151.35 m S (for the first one for example). > I would really appreciate some help. > Best wishes, > > Romina. > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > [[alternative HTML version deleted]]
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