elk: SRTMtopo, domain for latitude/ longitude

Hey guys,

I want to use the elk component SRTMtopo with a srtm3 file. I can get the points for the surface i want to create but i wonder what values i should set as domains. Are that the coordinates of my project site or do i have to enter the coordinates of the whole tile (http://dds.cr.usgs.gov/srtm/version2_1/Documentation/Continent_def.gif) i set as file? And how can i get my project site then?

Many thanks in advance!

B