[R-sig-Geo] Converting UTM to geographical coordinates

Manuel Spínola mspinola10 at gmail.com
Sun Oct 17 01:34:25 CEST 2010


  Thank you very much Robert,

I need CRTM05 and according the information that you sent me it will be:

+proj=tmerc  + lon_0=-84 + lat_0=0 + k=0.9999 +datum=WGS84

I guess I only need to set the 0.9999 instead of 0.9996.

It make sense?

Best,

Manuel

On 16/10/2010 02:32 p.m., Robert J. Hijmans wrote:
> Manuel,
>
> Costa Rica Transverse Mercator is a type of Transverse Mercator (like 
> UTM).
>
> http://www.remotesensing.org/geotiff/proj_list/transverse_mercator.html
>
> So we have, in proj.4 notation
>
> +proj=tmerc
>
> It is revealed here: 
> http://www.asprs.org/resources/GRIDS/04-2008-costarica.pd 
> <http://www.asprs.org/resources/GRIDS/04-2008-costarica.pdf>
>
> that the for *
> "Proyección CRTM90-WGS84" the
> *central meridian is 84 degrees so we have:
>
> +proj=tmerc *
> +lon_0=-84
> *
> *
> *
> *
> The same author and the document below (a search for "Proyección CRTM90-WGS84" )
> *
> *
>
>
> *
> *http://www.geotecnologias.com/Documentos/TSCArcGIS_9x.pdf*
>
> provide some additional info such that I would think you are probably 
> dealing with :
> *
> +proj=tmerc *
> +lon_0=-84 +lat_0=0
> **
> +k=0.9996 +datum=WGS84
> *
> *
>
> Although there might be *
> CRTM90 projections with a different datum out there. And watch for those false eastings and northings (horizontal and/or vertical shifts to express the coordinates in smaller numbers. (I am assuming +
> **
> *
> x_0=0/  /+y_0=0*
> **
> )
> *
>
> http://spatialreference.org/ 
> <http://spatialreference.org/ref/sr-org/6993/> did not have it, but I 
> have uploaded here, so that you can easily test it by clicking on a map:
>
> http://spatialreference.org/ref/sr-org/6993/
>
> With this you could try your luck with spTransform
>
> Best, Robert
>
>
> On Sat, Oct 16, 2010 at 7:45 AM, Manuel Spínola <mspinola10 at gmail.com 
> <mailto:mspinola10 at gmail.com>> wrote:
>
>     Thank you very much Alexander.
>     I am looking at the website right now.
>     In my case I have a very particular coordinate system (CRTM, Costa
>     Rica Transverse MErcator) in this case, which parameter I need to
>     know to make the conversion?
>
>     Best,
>
>     Manuel
>
>
>     On 16/10/2010 05:41 a.m., Alexandre Villers wrote:
>>     Hey Manual,
>>
>>     One thing to do first would be to ask where you can find the
>>     information... here for example
>>     http://rwiki.sciviews.org/doku.php?id=tips:spatial-data:change_crs everything
>>     you look for is on that page
>>     And have a look a Applied Spatial Data Analysis with R (ASDAR) to
>>     understand the basics of Spatial objects in sp package and how to
>>     perform what you are looking for. It will be much more benefitial
>>     for you to learn it by yourself that simply copy a code one can
>>     provide you with...
>>
>>     HTH
>>
>>     Best regards
>>
>>     Alex
>>
>>     -- 
>>     Alexandre Villers, PhD.
>>     Postdoc researcher
>>     Spatial Ecology & Population Dynamics
>>     Section of Ecology, Department of Biology
>>     University of Turku
>>     FIN-20014 Turku
>>     Finland
>>
>>     @mail: alexandre.villers at utu.fi <mailto:alexandre.villers at utu.fi>
>>     phone: 00358 (0)2 333 5049
>>
>>     Skype You can skype me (but think of using Ekiga instead !)
>>
>>
>>     *Use open source and free softwares*
>>     <http://cran.r-project.org/> <http://grass.itc.it/>
>>     <http://www.qgis.org/> <http://fr.openoffice.org/>
>>     <http://www.mozilla-europe.org/fr/>
>>     <http://www.mozilla-europe.org/fr/>
>>
>>
>>     _______________________________________________
>>     R-sig-Geo mailing list
>>     R-sig-Geo at stat.math.ethz.ch  <mailto:R-sig-Geo at stat.math.ethz.ch>
>>     https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>
>     -- 
>     *Manuel Spínola, Ph.D.*
>     Instituto Internacional en Conservación y Manejo de Vida Silvestre
>     Universidad Nacional
>     Apartado 1350-3000
>     Heredia
>     COSTA RICA
>     mspinola at una.ac.cr <mailto:mspinola at una.ac.cr>
>     mspinola10 at gmail.com <mailto:mspinola10 at gmail.com>
>     Teléfono: (506) 2277-3598
>     Fax: (506) 2237-7036
>     Personal website: Lobito de río
>     <https://sites.google.com/site/lobitoderio/>
>     Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>
>
>     _______________________________________________
>     R-sig-Geo mailing list
>     R-sig-Geo at stat.math.ethz.ch <mailto:R-sig-Geo at stat.math.ethz.ch>
>     https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>


-- 
*Manuel Spínola, Ph.D.*
Instituto Internacional en Conservación y Manejo de Vida Silvestre
Universidad Nacional
Apartado 1350-3000
Heredia
COSTA RICA
mspinola at una.ac.cr
mspinola10 at gmail.com
Teléfono: (506) 2277-3598
Fax: (506) 2237-7036
Personal website: Lobito de río 
<https://sites.google.com/site/lobitoderio/>
Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>
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