Issue 74509

Summary: Chart2: Logarithmic Scale, various bases for LOG
Product: General Reporter: discoleo <discoleo>
Component: chartAssignee: AOO issues mailing list <issues>
Status: CONFIRMED --- QA Contact:
Severity: Trivial    
Priority: P3 CC: issues,
Version: 3.3.0 or older (OOo)   
Target Milestone: ---   
Hardware: All   
OS: All   
Issue Type: FEATURE Latest Confirmation in: ---
Developer Difficulty: ---

Description discoleo 2007-02-13 20:59:33 UTC
*Logarithmic Scale* - Different Bases

Chart2 Reimplementation
This feature request should be integrated into the "Scales and Intervals
Specification" (

When using a logarithmic scale, the logarithm base is usually 10. Most of the
time this is indeed the way it should be, because at a log step of 1, the data
changes by a factor of 10. (=> therefore easy visualisation)

However, there are some situations where a different base for the logarithm is

When working with audio frequencies, the frequency often doubles. To accommodate
this, the base of the logarithm must be 2. One common example is that of an
audiogram. The frequencies recorded are usually: 125 Hz, 250 Hz, 500 Hz, 1000
Hz, 2000 Hz, 4000 Hz and 8000 Hz. For an example of an audiogram see . Please note, that both
the x-axis and the y-axis of the audiogram are logarithmic.

Log2 is also often used in computer sciences, see e.g. (the
graphic on blogging) and in other branches, where doubling time is relevant
(e.g. pharmacodynamics, epidemiology).

Some other bases might also be useful, like e (=2.72...).

1. ability to choose the base of the logarithmic scale
2. DEFAULT: checkbox with base 10 (this is the most useful, therefore checked by
3. base 2 (checkbox unchecked)
4. natural logarithm (base e, checkbox unchecked)
5. custom value: field to type a number ( greater then 1; I believe numbers
between (0,1) are very rarely used, IF at all)
Comment 1 IngridvdM 2007-02-14 11:14:11 UTC
yes, I think that would be a useful feature in future
Comment 2 IngridvdM 2007-02-14 11:15:10 UTC
Comment 3 IngridvdM 2008-07-22 14:22:08 UTC
reset to new
Comment 4 blayde 2008-09-24 00:26:22 UTC
this is already mostly implemented - it's just not intuitive...

you have to set the major interval to log10(x^2)-log10(x) where x is the base
you'd like

 base 10 would have a major interval of 1.0 (duh)
 base 2 would have a major interval of 0.30102999566398
 base e would have a major interval of 0.43429448190325

i think the ui changes requested here should just update the major interval
because that would be very easy to implement and quite intuitive

the only problem i can think of is somehow making the labels in terms of e when
using that as the base since all the decimal stuff would be confusing