[R-sig-Geo] projection

[Roger Bivand]

On Tue, 18 May 2010, Heuvelink, Gerard wrote:

> Dear list,
>
> I hope someone can help me with the following.
>
> I have an SRTM DEM of Turkey in the "ED 1950 Lambert Conformal Conic"
> projection system.

See: http://www.asprs.org/resources/GRIDS/, September 2006. The third page 
gives the ED50 to ETRS89 seven-parameter values for the +towgs84= 
component. What you do not have to set up a +proj=lcc ... is the +lat_0=, 
+lon_0=, and so on. Without those, you have no chance of success. Obtain 
then from your data source. They must be assumed to have known what they 
were doing, as the input SRTM were not projected.

Roger

>
> However, I do not know how this is referred to in R. For example, I
> might load the dem as:
>
> DEM = readGDAL("srtm_5km_ascii.txt")
>
> Next I will want to let know what projection it is by issuing:
>
> proj4string(DEM) = XXXXXXXXXXX
>
> What do I write for XXXXXXXX?
>
> Thanks, Gerard
>
>
> Gerard B.M. Heuvelink
> Environmental Sciences Group
> Wageningen University and Research Centre
> P.O. Box 47
> 6700 AA Wageningen
> The Netherlands
>
> tel +31 317 486538 Mon Tue
> tel +31 317 482716 Wed Thu Fri
>
> email gerard.heuvelink at wur.nl <mailto:gerard.heuvelink at wur.nl>
> http://www.lad.wur.nl/UK/ <http://www.lad.wur.nl/UK/>
> http://www.alterra.wur.nl/NL/onderzoek/Werkveld+Bodem/TBGE/Gerard+Heuvel
> ink/
> <http://www.alterra.wur.nl/NL/onderzoek/Werkveld+Bodem/TBGE/Gerard+Heuve
> link/>
>
>
>
>
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>
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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