[R-sig-Geo] make_EPSG chile

[Roger Bivand]

On Mon, 28 Jan 2013, Mauricio Zambrano-Bigiarini wrote:

> On 27/01/13 22:09, Orietta Nicolis wrote:
>> Dear R users,
>> 
>> 
>> I'm trying to run the following example with data of Chile, but I didn't
>> find a EPSG code for this country which could be used in R.
>> 
> Hi Orietta,
>
> AFAIK, in Chile there are two main local projections:
>
> PSAD56 / UTM zone 18S, and
> PSAD56 / UTM zone 19S

But:

> EPSG <- make_EPSG()
> EPSG[grep("Chile", EPSG$note), 1:2]
      code                          note
450  5360                # SIRGAS-Chile
2697 5361 # SIRGAS-Chile / UTM zone 19S
2698 5362 # SIRGAS-Chile / UTM zone 18S

all of which are WGS84 - do we know whether the +ellps in Orietta's data 
is GRS80 or your earlier intl?

With PROJ.4 4.8.0, we get a later EPSG too, with:

> CRS("+init=epsg:24879")
CRS arguments:
  +init=epsg:24879 +proj=utm +zone=19 +south +ellps=intl
+towgs84=-288,175,-376,0,0,0,0 +units=m +no_defs

which can be transformed to WGS84.

Roger

>
> which are used depending on the latitude you are working on.
>
> For PSAD56_Z19S, you may try:
>
> library(sp)
> psad56.p4s <- CRS("+proj=utm +zone=19 +south +ellps=intl +units=m +no_defs")
>
> which is equivalent to use EPSG:24879
>
> if you need higher precision, you may need to add the '+towgs84' argument to 
> 'psad56.p4s'
>
> Saludos,
>
> Mauricio
>
> PS,
> I'm happy to know there are people in Chile using R !
>
>

-- 
Roger Bivand
Department of Economics, NHH Norwegian School of Economics,
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