[GRASSLIST:3201] Re: bathymetry

[Hamish]

> I am using GRASS 5.0.0 on a mac (10.2.8).  I am not sure what you mean
> by datum support.

for a better explanation than I could give you, see:
http://biology.usgs.gov/geotech/documents/datum.html


> I thought that I specified the datum for a location
> when I set it up.  Do you mean that I can not project across datums
> when using a command like r.proj?

Not with GRASS 5.0.0, maybe there is limmited NAD27 and NAD83 support?
Someone else would have to answer that, but generally no; you need a
newer version of GRASS for r.proj to handle transformations between
different datums correctly.

 
> the address for this data is here
> 
> http://topex.ucsd.edu/marine_topo/mar_topo.html

cheers. 

Some projection and datum info is here:
ftp://topex.ucsd.edu/pub/global_topo_2min/arcinfo.html




Hamish