74509
2007-02-13 20:59:33 +0000
Chart2: Logarithmic Scale, various bases for LOG
2013-09-25 20:41:41 +0000
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Code
General
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3.3.0 or older (OOo)
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P3
Trivial
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discoleo
issues
issues
tony.galmiche.ooo
FEATURE
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1771985
0
discoleo
2007-02-13 20:59:33 +0000
*Logarithmic Scale* - Different Bases
TARGET
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Chart2 Reimplementation
This feature request should be integrated into the "Scales and Intervals
Specification" (http://specs.openoffice.org/chart/Chart_Scales_and_Intervals.odt)
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
needed.
EXAMPLE
=======
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
http://www.sfu.ca/sonic-studio/handbook/Audiogram.html . 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.
http://logbase2.blogspot.com/2005/12/double-double-toil-and-trouble.html (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...).
REQUIREMENTS
============
1. ability to choose the base of the logarithmic scale
2. DEFAULT: checkbox with base 10 (this is the most useful, therefore checked by
default)
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)
1771986
1
IngridvdM
2007-02-14 11:14:11 +0000
yes, I think that would be a useful feature in future
1771987
2
IngridvdM
2007-02-14 11:15:10 +0000
accepted
1771988
3
IngridvdM
2008-07-22 14:22:08 +0000
reset to new
1771989
4
da.blayde
2008-09-24 00:26:22 +0000
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