« Return to Thread: q:how are decimal places calculated on Y-axis? (how to influence)?
Re: q:how are decimal places calculated on Y-axis? (how toinfluence)?
by Alex van den Bogaerdt-2
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----- Original Message -----
From: "Pablo Sanchez" <pablo@...>
To: <rrd-users@...>
Sent: Friday, June 19, 2009 6:04 PM
Subject: [rrd-users] q:how are decimal places calculated on Y-axis? (how
toinfluence)?
> 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? :)
I got intrigued by this question and I just knew I've seen this happen in
the past. I found version 1.2.23 on my antique fedora machine and wrote this
small script. Try it.
rrdtool create test.rrd --start 1245448800 DS:test:GAUGE:300:U:U
RRA:AVERAGE:0:1:10
rrdtool update test.rrd 1245449100:29.97
rrdtool update test.rrd 1245449400:29.96
rrdtool update test.rrd 1245449700:29.95
rrdtool update test.rrd 1245450000:29.94
rrdtool update test.rrd 1245450300:29.95
rrdtool update test.rrd 1245450600:29.96
rrdtool update test.rrd 1245450900:29.97
rrdtool update test.rrd 1245451200:29.98
rrdtool update test.rrd 1245451500:29.99
set `rrdtool graph whatever DEF:test=test.rrd:test:AVERAGE
PRINT:test:MIN:%6.2lf PRINT:test:MAX:%6.2lf`
rrdtool graph test.png --start 1245448800 --end 1245451500 \
--title "min $2 max $3" \
--lower-limit $2 \
--upper-limit $3 \
--rigid \
--alt-y-grid \
DEF:test=test.rrd:test:AVERAGE \
LINE1:test#FF0000:test
Both alt-y-grid and rigid seem to be necessary, my initial suggestion of
using -L was not.
If you don't need the scale to be 'dynamic', you can leave out that 1st
rrdtool command and just use fixed numbers in the 2nd call.
HTH
Alex
_______________________________________________
rrd-users mailing list
rrd-users@...
https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
From: "Pablo Sanchez" <pablo@...>
To: <rrd-users@...>
Sent: Friday, June 19, 2009 6:04 PM
Subject: [rrd-users] q:how are decimal places calculated on Y-axis? (how
toinfluence)?
> 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? :)
I got intrigued by this question and I just knew I've seen this happen in
the past. I found version 1.2.23 on my antique fedora machine and wrote this
small script. Try it.
rrdtool create test.rrd --start 1245448800 DS:test:GAUGE:300:U:U
RRA:AVERAGE:0:1:10
rrdtool update test.rrd 1245449100:29.97
rrdtool update test.rrd 1245449400:29.96
rrdtool update test.rrd 1245449700:29.95
rrdtool update test.rrd 1245450000:29.94
rrdtool update test.rrd 1245450300:29.95
rrdtool update test.rrd 1245450600:29.96
rrdtool update test.rrd 1245450900:29.97
rrdtool update test.rrd 1245451200:29.98
rrdtool update test.rrd 1245451500:29.99
set `rrdtool graph whatever DEF:test=test.rrd:test:AVERAGE
PRINT:test:MIN:%6.2lf PRINT:test:MAX:%6.2lf`
rrdtool graph test.png --start 1245448800 --end 1245451500 \
--title "min $2 max $3" \
--lower-limit $2 \
--upper-limit $3 \
--rigid \
--alt-y-grid \
DEF:test=test.rrd:test:AVERAGE \
LINE1:test#FF0000:test
Both alt-y-grid and rigid seem to be necessary, my initial suggestion of
using -L was not.
If you don't need the scale to be 'dynamic', you can leave out that 1st
rrdtool command and just use fixed numbers in the 2nd call.
HTH
Alex
_______________________________________________
rrd-users mailing list
rrd-users@...
https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
« Return to Thread: q:how are decimal places calculated on Y-axis? (how to influence)?
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