[GRASSLIST:3422] srtm30 world data (was correct big holes in srtm data)

[tatel at euskalnet.net]

Hi all

Markus wrote:
> In case srtm30 data are available .... (only US AFAIK).

See http://edcftp.cr.usgs.gov/pub/data/srtm/SRTM30/

It seems to have entire world, but since I don't know about GTOPO30 may 
be not all tiles are updated... 

Best regards,

Roman