From: Eric Firing <efiring@ha...>  20100915 17:37:19

On 09/15/2010 04:55 AM, Benjamin Root wrote: > On Tue, Sep 14, 2010 at 11:12 AM, Jan Skowron <jan.skowron@... > <mailto:jan.skowron@...>> wrote: > > Hi, > apropos this offset discussion. > matplotlib makes offsets not aligned to the full tens or some other > easy number with small amount of nonzero digits in front? > > For example having ticks: > 4917, 4918, 4919, 4920, 4921, 4922 > > it will now display: > 1, 2, 3, 4, 5, 6 with offset 4916 (of even +4.916e3) > > this makes reading values on the axis really really hard as every time > one have to perform not obvious summations with all digits of length. > It would be beneficial to have as a default behaviour some > optimization of offsets to have it as some basic number for easy > reading instead of current behaviour that tries to minimize the number > of digits in the ticks and starts from a low number like 1 or 0.05 or > so. > In our case the best display would be: > > 17, 18, 19, 20, 21, 22 with offset 4900 > > So we minimize the number of nonzero digits in offset and not a > number of digits in tick labels. > > Another more ridiculous example (from life) are ticks with values: > > 4916.25, 4916.30, 4916.35, 4916.40, 4916.45 > > are displayed as: > > 0.05, 0.10, 0.15, 0.20, 0.25 with offset +4.9162e3 > > and with good algorithm should be displayed as: > > 0.25, 0.30, 0.35, 0.40, 0.45 with offset 4962 (nottice that not > +4.962e3 as it usually displays now) > > and if we would cross the boundary between 4962 and 4963 than ticks > should look like: > 2.80, 2.85, 2.90, 2.95, 3.00, 3.05 with offset 4960 > > > In my opinion the current behaviour of offsets really hampers the > usability of these at all, and probably 90% of users spent some time > on nothing but trying to figure out how to turn this thing off (thanks > for sending this solutions here). > > So this is message to signal or show the need for fixing this > algorithm. For now I think that the title of this post: "weird > behaviour in x axis", really summarize current offset algorithm > nicely. > > > Thanks for your comments, > Jan > > > I like that idea as it is certainly more intuitive. Essentially, it > would find the most significant bits that are common to all ticks and > use that for the offset. > > Does anybody know where the current code is? I would be willing to take > a look at it today and see what I can do. In ticker.ScalarFormatter._setOffset (or something like that). Be careful not to make it too complicated; maybe it can even be made simpler. I think that as a first shot, something like adding +3 (or maybe it would be 3) to a couple lines of code might be a step in the right directionand maybe adequate. Thank you. Eric > > Thanks, > Ben Root > > > >  > Start uncovering the many advantages of virtual appliances > and start using them to simplify application deployment and > accelerate your shift to cloud computing. > http://p.sf.net/sfu/novellsfdev2dev > > > > _______________________________________________ > Matplotlibusers mailing list > Matplotlibusers@... > https://lists.sourceforge.net/lists/listinfo/matplotlibusers 