[rrd-users] q:how are decimal places calculated on Y-axis? (how to influence)?

[Pablo Sanchez]

Howdy,

I have a barometric graph which can display results in hPA or inHG.  I
store the data in hPA and use a CDEF to convert it to inHG when
requested.

My problem is that for the graph period, the `inHG' value may vary
only slightly:

     max:  29.97
     min:  29.88

I've tinkered with `--y-grid' to get better grid steps (before I was
only getting one line at 30 and the resulting graphed line was very
flat.  :):

   --y-grid .01:5

and the line graphs very well.  However, the y-axis labels seem to be
rounded.  Here's an example of what I see versus what I'd like:

    Wanted     Rendered
    ------     --------
    30.05         30
    30.00         30
    29.95         30
    29.90         30
    29.85         30
    29.80         30

I've tried using the `--alt-y-grid' option but that didn't help.

I'm using a very old version of RRD on this weather-station laptop:
1.2.23 

Am I missing an obvious `rrdtool graph' switch or is this a bug in
this very old version of RRD?  :)

Please advise.

Note, I tried compiling the 1.3 version on this openSUSE 10.3 machine
and it resulted with no data being logged.  Quite strange.  So I went
back to thee 1.2.23 version - I even disabled nmap ...

Cheers,
-- 
Pablo Sanchez - Blueoak Database Engineering, Inc
Ph:    819.459.1926      Fax:   760.860.5225 (US)