[R-sig-Geo] spTransform results

[Roger Bivand]

On Tue, 20 May 2008, Sylvia Churcher wrote:

> 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
> reference
>
> *coords.x1 is long (vector name:  lake.info$Longitude_W);
> coords.x2 is lat (vector name:  lake.info$Latitude_N)
>
> SpatialPoints:
>      coords.x1 coords.x2
> [1,]     89.59     46.02
> [2,]     89.67     46.12

            ^^^^^

These look like Sinkiang to me - or a more recent translitteration. GE 
goes to Western China too if you type 89.59E 46.02N; 89.59W is near Vilas 
WI. If they are degrees W, they ought to be negative.

Hope this helps,

Roger

>
> 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:
> SpatialPoints:
>      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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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no