[GRASS-dev] S-JTSK strikes back

[Martin Landa]

Hi,

I tried

2007/5/3, Markus Neteler <neteler at itc.it>:

> # 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

g.proj epsg=2065 -c loc=s-jtsk datum=3

g.gisenv | grep LOC
LOCATION_NAME='s-jtsk';

g.proj -w

I got different values...

> g.proj -w
>         DATUM["unknown",
>             SPHEROID["Bessel_1841",6377397.155,299.1528128]],
>         PRIMEM["Greenwich",0],
>         UNIT["degree",0.0174532925199433]],

        DATUM["Militar_Geographische_Institut",
            SPHEROID["Bessel_1841",6377397.155,299.1528128]],
        PRIMEM["ferro",-17.666666666668],
        UNIT["degree",0.0174532925199433]],

    PARAMETER["longitude_of_center",24.833333333332], <- This should
be 42.5 (because of Ferro)

I am wonder why g.proj -w gives different values...

g.proj -jf
+proj=krovak +lat_0=49.5 +lon_0=42.5 +k=0.9999 +x_0=0 +y_0=0 +pm=ferro
+no_defs +a=6377397.155 +rf=299.1528128
+towgs84=570.8,85.7,462.8,4.998,1.587,5.261,3.56 +to_meter=1

Martin

> 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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-- 
Martin Landa <landa.martin at gmail.com> * http://gama.fsv.cvut.cz/~landa *