[GRASSLIST:6894] Re: v.proj problem

[Paul Kelly]

As far as I can remember, v.proj in 6.x has a "feature" that it interprets 
the z co-ordinate of 3-D vectors as ellipsoidal height and tries to 
convert it as part of the re-projection. In most cases this 
interpretation will probably not  be correct. There really should be a 
command-line flag to say 'interpret z co-ordinate as ellipsoidal height 
and transform accordingly'.

Normally you would expect the z co-ordinate to remain unchanged, the way 
I'm looking at it. I could be missing something though.

Not sure if this is related to you problem but thought I should mention 
it.

Paul


On Thu, 26 May 2005, Francesco Mirabella wrote:

> Hi to all,
> I have reprojected 3d vector points from wgs84 lat long location to
> utm33:
>
> -in the UTM 33 location:
> v.proj input=data_wgs84  output=data_utm33 location=WGS_84_latlong mapset=PERMANENT
>
> I got the following error:
> ##################################
> Input Projection Parameters: +proj=latlong +a=6378137 +rf=298.257223563
> +no_defs +towgs84=0.000,0.000,0.000
> Input Unit Factor: 1
>
> Output Projection Parameters: +proj=utm +zone=33 +a=6378388 +rf=297
> +no_defs +towgs84=-87.000000,-98.000000,-121.000000
> Output Unit Factor: 1
>
> Creating vector file...
> pj_transform() failed
> cause: geocentric transformation missing z or ellps
> Error in pj_do_transform
> GRASS 6.0.0 (umbmar):~ >
> ##################################
>
> can someone help?
> Francesco
>
> p.s.
> I did v.proj transformations some other times from the same location
> into the utm33 location, but it is the first time that this error
> occurred.
>
>