[GRASS-dev] S-JTSK strikes back

[Paul Kelly]

On Thu, 3 May 2007, Markus Neteler wrote:

> Hi,
>
> for a project I need to define a S-JTSK location. I thought
> that we resolved this recently, but apparently not:
>
> # S-JTSK (Ferro) / Krovak
> <2065> +proj=krovak +lat_0=49.5 +lon_0=42.5 +alpha=30.28813972222222 +k=0.9999 +x_0=0 +y_0=0 +ellps=bessel +pm=ferro +units=m +no_defs  <>
>
> So I do:
>
> g.proj epsg=2065

Hello Markus,
As far as I can remember it was only resolved in so far as we decided that 
you couldn't create a Krovak location using EPSG codes and it needed to be 
done manually using g.setproj? This was because of problems translating 
WKT into a PROJ.4 description inside OGR, partly related to the fact that 
"proj=krovak" is still kind of temporary and has various paramters 
hard-coded in it and a good flexible translation will require to use the 
new "proj=kocc" when it is eventually merged into PROJ.4. But if you think 
there is more to it than this then I can look into it more.

Paul

>
> g.proj -w
> PROJCS["Krovak",
>    GEOGCS["bessel",
>        DATUM["unknown",
>            SPHEROID["Bessel_1841",6377397.155,299.1528128]],
>        PRIMEM["Greenwich",0],
>        UNIT["degree",0.0174532925199433]],
>    PROJECTION["Krovak"],
>    PARAMETER["latitude_of_center",49.5],
>    PARAMETER["longitude_of_center",24.83333333333333],
>    PARAMETER["azimuth",0],
>    PARAMETER["pseudo_standard_parallel_1",0],
>    PARAMETER["scale_factor",0.9999],
>    PARAMETER["false_easting",0],
>    PARAMETER["false_northing",0],
>    UNIT["Meter",1]]
>
> This is not quite right. It should be
> http://lists.maptools.org/pipermail/proj/2003-February/000626.html
> something like this:
> PROJCS["S-JTSK (Ferro) / Krovak",
>     GEOGCS["S-JTSK (Ferro)",
>         DATUM["S_JTSK_Ferro",
>             SPHEROID["Bessel 1841",6377397.155,299.1528128,
>                 AUTHORITY["EPSG","7004"]],
>             AUTHORITY["EPSG","6818"]],
>         PRIMEM["Ferro",-17.66666666666667,
>             AUTHORITY["EPSG","8909"]],
>         UNIT["degree",0.0174532925199433],
>         AUTHORITY["EPSG","4818"]],
>     PROJECTION["Krovak"],
>     PARAMETER["latitude_of_center",49.5],
>     PARAMETER["longitude_of_center",42.5],
>     PARAMETER["azimuth",30.28813972222222],
>     PARAMETER["pseudo_standard_parallel_1",78.5],
>     PARAMETER["scale_factor",0.9999],
>     PARAMETER["false_easting",0],
>     PARAMETER["false_northing",0],
>     UNIT["metre",1,
>         AUTHORITY["EPSG","9001"]],
>     AUTHORITY["EPSG","2065"]]
>
> Is any name remapping still missing in
> lib/proj/convert.c
> ?
>
> Markus
>
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