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converting coordinates from utm to longitude / latitude

Werner
Hi,

is there a function in R to convert data read with read.shape and which is originally in UTM coordinates into longitude / latitude coordinates?
I found the convUL() function from the PBSmapping package but I have no idea how I could apply that to the read.shape object.

Many thanks,
  Werner


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Re: converting coordinates from utm to longitude / latitude

Werner
It would be nicer to convert directly the entire shapefile object to long/lat coordinates but if that is not possible, I will convert the other points to UTM.
Hence, I am playing around with rgdal.

library(rgdal)
SP <- SpatialPoints(cbind(32.29252, -0.3228500),
  proj4string=CRS("+proj=longlat"))
spTransform(SP, CRS("+proj=utm +zone=36"))


> spTransform(SP, CRS("+proj=utm +zone=36"))
SpatialPoints:
     coords.x1 coords.x2
[1,]  421274.4 -35687.37
Coordinate Reference System (CRS) arguments: +proj=utm +zone=36 +ellps=WGS84

This result corresponds with what I get when using convUL() but my map of that area in UTM coordinates does not extend to the negative.
An external program converts the point to x=420994   y=9964407 which also seems correct with respect to the map. Fore sure, I am using the function wrongly somehow. Can anyone give me a hint?

That's very much appreciated!

Thanks,
   Werner



----- Ursprüngliche Mail ----
Von: Werner Wernersen <[hidden email]>
An: [hidden email]
Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
Betreff: converting coordinates from utm to longitude / latitude

Hi,

is there a function in R to convert data read with read.shape and which is originally in UTM coordinates into longitude / latitude coordinates?
I found the convUL() function from the PBSmapping package but I have no idea how I could apply that to the read.shape object.

Many thanks,
  Werner


______________________________
fügt über einen herausragenden Schutz gegen Massenmails.
http://mail.yahoo.com


__________________________________________________
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ragenden Schutz gegen Massenmails.
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Re: converting coordinates from utm to longitude / latitude

Dylan Beaudette-2
If you would like to convert the entire shapfile check out GDAL:

http://www.gdal.org/

http://casoilresource.lawr.ucdavis.edu/drupal/node/98

Cheers,

Dylan


On Tuesday 19 August 2008, Werner Wernersen wrote:

> It would be nicer to convert directly the entire shapefile object to
> long/lat coordinates but if that is not possible, I will convert the other
> points to UTM. Hence, I am playing around with rgdal.
>
> library(rgdal)
> SP <- SpatialPoints(cbind(32.29252, -0.3228500),
>   proj4string=CRS("+proj=longlat"))
> spTransform(SP, CRS("+proj=utm +zone=36"))
>
> > spTransform(SP, CRS("+proj=utm +zone=36"))
>
> SpatialPoints:
>      coords.x1 coords.x2
> [1,]  421274.4 -35687.37
> Coordinate Reference System (CRS) arguments: +proj=utm +zone=36
> +ellps=WGS84
>
> This result corresponds with what I get when using convUL() but my map of
> that area in UTM coordinates does not extend to the negative. An external
> program converts the point to x=420994   y=9964407 which also seems correct
> with respect to the map. Fore sure, I am using the function wrongly
> somehow. Can anyone give me a hint?
>
> That's very much appreciated!
>
> Thanks,
>    Werner
>
>
>
> ----- Ursprüngliche Mail ----
> Von: Werner Wernersen <[hidden email]>
> An: [hidden email]
> Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
> Betreff: converting coordinates from utm to longitude / latitude
>
> Hi,
>
> is there a function in R to convert data read with read.shape and which is
> originally in UTM coordinates into longitude / latitude coordinates? I
> found the convUL() function from the PBSmapping package but I have no idea
> how I could apply that to the read.shape object.
>
> Many thanks,
>   Werner
>
>
> ______________________________
> fügt über einen herausragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
>
> __________________________________________________
> Do
> ragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html and provide commented, minimal,
> self-contained, reproducible code.



--
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: converting coordinates from utm to longitude / latitude

Jim Regetz
In reply to this post by Werner
Werner Wernersen wrote:

> It would be nicer to convert directly the entire shapefile object to long/lat coordinates but if that is not possible, I will convert the other points to UTM.
> Hence, I am playing around with rgdal.
>
> library(rgdal)
> SP <- SpatialPoints(cbind(32.29252, -0.3228500),
>   proj4string=CRS("+proj=longlat"))
> spTransform(SP, CRS("+proj=utm +zone=36"))
>
>
>> spTransform(SP, CRS("+proj=utm +zone=36"))
> SpatialPoints:
>      coords.x1 coords.x2
> [1,]  421274.4 -35687.37
> Coordinate Reference System (CRS) arguments: +proj=utm +zone=36 +ellps=WGS84
>
> This result corresponds with what I get when using convUL() but my map of that area in UTM coordinates does not extend to the negative.
> An external program converts the point to x=420994   y=9964407 which also seems correct with respect to the map. Fore sure, I am using the function wrongly somehow. Can anyone give me a hint?

It looks like you are specifying 36S in your external program, and
(implicitly) 36N in R. Using your SP from above, note the following:

 > spTransform(SP, CRS("+proj=utm +zone=36 +north"))
SpatialPoints:
      coords.x1 coords.x2
[1,]  421274.4 -35687.37
Coordinate Reference System (CRS) arguments: +proj=utm +zone=36
+ellps=WGS84

 > spTransform(SP, CRS("+proj=utm +zone=36 +south"))
SpatialPoints:
      coords.x1 coords.x2
[1,]  421274.4   9964313
Coordinate Reference System (CRS) arguments: +proj=utm +zone=36 +south
+ellps=WGS84

The latter gets in the ballpark of output from your external program.
I'd speculate that the remaining differences owe to different
assumptions about e.g. the datum (WGS84 for the R statements given
above), but I must admit I'm not a geographer.

Hope that helps,
Jim

> That's very much appreciated!
>
> Thanks,
>    Werner
>
>
>
> ----- Ursprüngliche Mail ----
> Von: Werner Wernersen <[hidden email]>
> An: [hidden email]
> Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
> Betreff: converting coordinates from utm to longitude / latitude
>
> Hi,
>
> is there a function in R to convert data read with read.shape and which is originally in UTM coordinates into longitude / latitude coordinates?
> I found the convUL() function from the PBSmapping package but I have no idea how I could apply that to the read.shape object.
>
> Many thanks,
>   Werner
>
>
> ______________________________
> fügt über einen herausragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
>
> __________________________________________________
> Do
> ragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: converting coordinates from utm to longitude / latitude

Werner
In reply to this post by Werner
You were absolutely right. If I use south everything is fine. That once again proves the danger of intuition. I simply assumed since almost all of the map is on the northern half that the projection should use north as well. But that is apparently wrong. I couldn't find any description of these definition string parameters which could have been informative. Since I am not a geographer either, I probably used the wrong terms for searching.

Anyway, now it works.
Thanks so much for the help, Jim!

Best regards,
  Werner



----- Ursprüngliche Mail ----
Von: Jim Regetz <[hidden email]>
An: Werner Wernersen <[hidden email]>
CC: [hidden email]
Gesendet: Mittwoch, den 20. August 2008, 03:08:48 Uhr
Betreff: Re: converting coordinates from utm to longitude / latitude

Werner Wernersen wrote:

> It would be nicer to convert directly the entire shapefile object to long/lat coordinates but if that is not possible, I will convert the other points to UTM.
> Hence, I am playing around with rgdal.
>
> library(rgdal)
> SP <- SpatialPoints(cbind(32.29252, -0.3228500),
>   proj4string=CRS("+proj=longlat"))
> spTransform(SP, CRS("+proj=utm +zone=36"))
>
>
>> spTransform(SP, CRS("+proj=utm +zone=36"))
> SpatialPoints:
>      coords.x1 coords.x2
> [1,]  421274.4 -35687.37
> Coordinate Reference System (CRS) arguments: +proj=utm +zone=36 +ellps=WGS84
>
> This result corresponds with what I get when using convUL() but my map of that area in UTM coordinates does not extend to the negative.
> An external program converts the point to x=420994   y=9964407 which also seems correct with respect to the map. Fore sure, I am using the function wrongly somehow. Can anyone give me a hint?

It looks like you are specifying 36S in your external program, and
(implicitly) 36N in R. Using your SP from above, note the following:

> spTransform(SP, CRS("+proj=utm +zone=36 +north"))
SpatialPoints:
      coords.x1 coords.x2
[1,]  421274.4 -35687.37
Coordinate Reference System (CRS) arguments: +proj=utm +zone=36
+ellps=WGS84

> spTransform(SP, CRS("+proj=utm +zone=36 +south"))
SpatialPoints:
      coords.x1 coords.x2
[1,]  421274.4   9964313
Coordinate Reference System (CRS) arguments: +proj=utm +zone=36 +south
+ellps=WGS84

The latter gets in the ballpark of output from your external program.
I'd speculate that the remaining differences owe to different
assumptions about e.g. the datum (WGS84 for the R statements given
above), but I must admit I'm not a geographer.

Hope that helps,
Jim

> That's very much appreciated!
>
> Thanks,
>    Werner
>
>
>
> ----- Ursprüngliche Mail ----
> Von: Werner Wernersen <[hidden email]>
> An: [hidden email]
> Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
> Betreff: converting coordinates from utm to longitude / latitude
>
> Hi,
>
> is there a function in R to convert data read with read.shape and which is originally in UTM coordinates into longitude / latitude coordinates?
> I found the convUL() function from the PBSmapping package but I have no idea how I could apply that to the read.shape object.
>
> Many thanks,
>   Werner
>
>
> ______________________________
> fügt über einen herausragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
>
> __________________________________________________
> Do
> ragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


________________________________________
ber einen herausragenden Schutz gegen Massenmails.
http://mail.yahoo.com
______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: converting coordinates from utm to longitude / latitude

Werner
In reply to this post by Werner
After having figured out that I had to download the proj.dll file additionally (it would be nice if they actually added a note to their readme) and setting the "+south" parameter, the conversion of the shapfile from UTM to long/lat with the ogr2ogr utility from gdal worked perfectly.

Thanks so much Dylan!
  Werner



----- Ursprüngliche Mail ----
Von: Dylan Beaudette <[hidden email]>
An: [hidden email]
CC: Werner Wernersen <[hidden email]>
Gesendet: Dienstag, den 19. August 2008, 23:29:34 Uhr
Betreff: Re: [R] converting coordinates from utm to longitude / latitude

If you would like to convert the entire shapfile check out GDAL:

http://www.gdal.org/

http://casoilresource.lawr.ucdavis.edu/drupal/node/98

Cheers,

Dylan


On Tuesday 19 August 2008, Werner Wernersen wrote:

> It would be nicer to convert directly the entire shapefile object to
> long/lat coordinates but if that is not possible, I will convert the other
> points to UTM. Hence, I am playing around with rgdal.
>
> library(rgdal)
> SP <- SpatialPoints(cbind(32.29252, -0.3228500),
>   proj4string=CRS("+proj=longlat"))
> spTransform(SP, CRS("+proj=utm +zone=36"))
>
> > spTransform(SP, CRS("+proj=utm +zone=36"))
>
> SpatialPoints:
>      coords.x1 coords.x2
> [1,]  421274.4 -35687.37
> Coordinate Reference System (CRS) arguments: +proj=utm +zone=36
> +ellps=WGS84
>
> This result corresponds with what I get when using convUL() but my map of
> that area in UTM coordinates does not extend to the negative. An external
> program converts the point to x=420994   y=9964407 which also seems correct
> with respect to the map. Fore sure, I am using the function wrongly
> somehow. Can anyone give me a hint?
>
> That's very much appreciated!
>
> Thanks,
>    Werner
>
>
>
> ----- Ursprüngliche Mail ----
> Von: Werner Wernersen <[hidden email]>
> An: [hidden email]
> Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
> Betreff: converting coordinates from utm to longitude / latitude
>
> Hi,
>
> is there a function in R to convert data read with read.shape and which is
> originally in UTM coordinates into longitude / latitude coordinates? I
> found the convUL() function from the PBSmapping package but I have no idea
> how I could apply that to the read.shape object.
>
> Many thanks,
>   Werner
>
>
> ______________________________
> fügt über einen herausragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
>
> __________________________________________________
> Do
> ragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html and provide commented, minimal,
> self-contained, reproducible code.



--
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341


__________________________________________________
Do You Yahoo!?
Sie sind
Massenmails.
http://mail.yahoo.com

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: converting coordinates from utm to longitude / latitude

Werner
In reply to this post by Werner
I forgot one more potentially time-saving hint if someone else wants to use org2org for such a conversion:
I found that only GDAL for Windows 1.4.4 works together with the proj.dll file which is downloadable from proj.4 but version 1.5 does not.



----- Ursprüngliche Mail ----
Von: Dylan Beaudette <[hidden email]>
An: [hidden email]
CC: Werner Wernersen <[hidden email]>
Gesendet: Dienstag, den 19. August 2008, 23:29:34 Uhr
Betreff: Re: [R] converting coordinates from utm to longitude / latitude

If you would like to convert the entire shapfile check out GDAL:

http://www.gdal.org/

http://casoilresource.lawr.ucdavis.edu/drupal/node/98

Cheers,

Dylan


On Tuesday 19 August 2008, Werner Wernersen wrote:

> It would be nicer to convert directly the entire shapefile object to
> long/lat coordinates but if that is not possible, I will convert the other
> points to UTM. Hence, I am playing around with rgdal.
>
> library(rgdal)
> SP <- SpatialPoints(cbind(32.29252, -0.3228500),
>   proj4string=CRS("+proj=longlat"))
> spTransform(SP, CRS("+proj=utm +zone=36"))
>
> > spTransform(SP, CRS("+proj=utm +zone=36"))
>
> SpatialPoints:
>      coords.x1 coords.x2
> [1,]  421274.4 -35687.37
> Coordinate Reference System (CRS) arguments: +proj=utm +zone=36
> +ellps=WGS84
>
> This result corresponds with what I get when using convUL() but my map of
> that area in UTM coordinates does not extend to the negative. An external
> program converts the point to x=420994   y=9964407 which also seems correct
> with respect to the map. Fore sure, I am using the function wrongly
> somehow. Can anyone give me a hint?
>
> That's very much appreciated!
>
> Thanks,
>    Werner
>
>
>
> ----- Ursprüngliche Mail ----
> Von: Werner Wernersen <[hidden email]>
> An: [hidden email]
> Gesendet: Dienstag, den 19. August 2008, 20:28:29 Uhr
> Betreff: converting coordinates from utm to longitude / latitude
>
> Hi,
>
> is there a function in R to convert data read with read.shape and which is
> originally in UTM coordinates into longitude / latitude coordinates? I
> found the convUL() function from the PBSmapping package but I have no idea
> how I could apply that to the read.shape object.
>
> Many thanks,
>   Werner
>
>
> ______________________________
> fügt über einen herausragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
>
> __________________________________________________
> Do
> ragenden Schutz gegen Massenmails.
> http://mail.yahoo.com
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html and provide commented, minimal,
> self-contained, reproducible code.



--
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341


__________________________________________________
Do You Yahoo!?
Sie sind
Massenmails.
http://mail.yahoo.com

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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