Slope form again!

[Houxiang Wang GEO Grad 96]

Sorry, I am back again.

My machine shut down, and all my former emails were lost. I still need help from 
you, especially the friend who has helped me a lot by directly sending email to 
my account, not to the list server. I sorry to say that I could not remember 
your name nor your email address. So I post the message here, and hope you would 
see it and help me out again.

With your great help I have got the sites file out of DEM. the format of data in 
the file looks like
		724675|4385245#259
		724725|4385245#259

But when I ran s.surf.tps, it says "ERROR: zero points in the given region!" The 
DEM I am using does not cover the entire region, i.e., in the DEM file, zero 
values (out of the county I am working on) mean no data. Does the above problem 
result from this?

I greatly appreciate your help.

Houxiang Wang

Miami University