[GRASS-dev] r.proj from GaussBoaga to UTM

[Hamish]

Christian Tiso wrote:
> Thank you markus, you're right, there's no datum
> definition:
> 
> GRASS 6.3.0 (fassaGB):~ > g.proj -w
> PROJCS["Transverse Mercator",
>     GEOGCS["international",
>         DATUM["unknown",
>            
> SPHEROID["International_1924",6378388,297]],
>         PRIMEM["Greenwich",0],
>         UNIT["degree",0.0174532925199433]],
....
> but this is beacause I created a new location from the GUI
> start panel of GRASS by choosing the "EPSG code"
> button and selectiong the 3003 code which should be the one
> related to the GaussBoaga, Rome 1940 Monte Mario
> projections.
> 
> Where am I wrong? It is not possible to create such a new
> location only by choosing the EPSG code?

The /usr/share/proj/epsg file's version of 3003 only defines the 1924
International ellipsoid, not the datum. so that's all grass knows about:

# Monte Mario / Italy zone 1
<3003> +proj=tmerc +lat_0=0 +lon_0=9 +k=0.9996 +x_0=1500000 +y_0=0 +ellps=intl +units=m +no_defs  <>


try  http://www.epsg-registry.org/  & go to "retrieve by code".

is "Monte Mario" aka "Rome 1940" datum? if so the epsg file may be faulty.
(don't know; ask on the proj4 mailing list)


grass's datum table has rome40:

# Rome 1940 (Sardinia Parameters)
rome40  "Monte_Mario"                     international dx=-225     dy=-65      dz=9

so you could run g.setproj in the PERMANENT mapset, choosing only to
change the datum and set it that way, or hack the PROJ_INFO file manually.


Hamish