[aprssig] Autoscaling on pressure graphs

[Steve Dimse]

findU now uses autoscaling for the barometric pressure graphs, e.g.

http://www.findu.com/cgi-bin/wxpage.cgi?call=K4HG&last=48

I've looked at a few dozen and all look good, but with thousands of  
weather stations and hundreds of last-hours options for each, it is  
obviously impossible to test for all possibilities. If you see  
something that looks bad, please email me the URL.

Thanks,

Steve K4HG