[R-sig-Geo] spTransform results

Sylvia Churcher CHURCHER at DAL.CA
Tue May 20 20:16:36 CEST 2008

Hello all,

Being a new and cautious user of the rgdal library I am having trouble
confirming that my results are correct.

transforming vectors with long and lat values to easting and northing in zone
16, datum=NAD83

I'll obviously omit the entire vectors, but include the first 2 lines for

*coords.x1 is long (vector name:  lake.info$Longitude_W);
coords.x2 is lat (vector name:  lake.info$Latitude_N)

      coords.x1 coords.x2
 [1,]     89.59     46.02
 [2,]     89.67     46.12

Using the code:
SP_grd <- SpatialPoints(cbind(lake.info$Longitude_W, lake.info$Latitude_N),
proj4string=CRS("+proj=longlat +datum=NAD83"))

SP_grd1 <- spTransform(SP_grd, CRS("+proj=utm +zone=16 +datum=NAD83"))

My result is:
      coords.x1 coords.x2
 [1,] -83121879 -53374442
 [2,] -82861240 -54157633

==> My main problem is that I'm not able to check that these resulting values
are correct and that I haven't made an error in my code.  The I've tried using
online converters and the results are not matching.  My lat and long points are
all for Wisconsin, USA (specifically zone 16T in NAD83).

Thank you any and all for your help.

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