Graphical library - charts

[przemolicc at poczta.fm-n-o-s-p-a-m]

Hello,

I have thousends of files with logs from monitoring system. Each file
has some important data (numbers). I'd like to create charts using those
numbers. Could you please suggest library which will allow creating
such charts ? The preferred chart is line chart.

Besides is there any library which allow me to zoom in/out of such chart ?
Sometimes I need to create chart using long-term data (a few months) but
then observe a minutes - it would be good to not create another short-term
chart but just zoom-in.

Those files are on one unix server and the charts will be displayed on
another unix server so the X-Window protocol is going to be used.

Any suggestions ?

Best regards
przemol