Re: Problems with ListPlot

*To*: mathgroup at smc.vnet.net*Subject*: [mg89047] Re: Problems with ListPlot*From*: igorvict at gmail.com*Date*: Sat, 24 May 2008 03:56:15 -0400 (EDT)*References*: <g11r71$adu$1@smc.vnet.net>

On May 21, 10:55 pm, Bill Rowe <readn... at sbcglobal.net> wrote: > On 5/20/08 at 6:53 AM, szhor... at gmail.com (Szabolcs Horv=C3=A1t) wrote= : > > >igorv... at gmail.com wrote: > >>I noticed the following problems when creating ListPlot in > >>Mathematica 6 (see the example): > >>ListPlot[{0, 1, 2}, PlotMarkers -> Style["\[FilledCircle]", > >>FontSize -> 12], Joined -> True, GridLines -> Automatic, PlotRange > >>-> {{1, 3}, {0.5, 1.5}}, PlotRangeClipping -> False, ImagePadding > >>-> 10] > >>1) The plot markers have an offset slightly to the left from their > >>correct position > >Precise positioning is not really achievable when glyphs from a font > >are used as plot markers. The problem can be cured by using > >graphics objects: > >PlotMarkers -> {Graphics[Circle[]], .05} > >Or if you need disks as plot markers, then just use a larger point > >size. > > Why not use > > PlotMarkers -> {Graphics[Disk[]], .05} > > if you want disks as plot markers instead of circles? > > >>2) In addition of 1 point and 1 line (2 other should be clipped as > >>they lie outside of the range) I see 2 points, where the line > >>crosses the lower and upper edges of the plot. > >I don't really understand this second question ... > > I think the original poster was thinking the graphic should be > consistent with: > > ListPlot[{0, 1, 2}, PlotMarkers -> {Graphics[Disk[]], .05}, > Joined -> True, GridLines -> Automatic, > PlotRange -> {{1, 3}, {0.5, 1.5}}] > > Notice the top and bottom disks are clipped since the specified > value of PlotRange isn't sufficient to fully include the top and > bottom disks. > > I believe the reason this was not seen using the original > poster's code was due to the inclusion of the ImagePadding > option and using PlotRangeClipping->False which combine so that > the top and bottom disks are not clipped. That is compare the > graphic using the code above to: > > ListPlot[{0, 1, 2}, PlotMarkers -> {Graphics[Disk[]], .05}, > Joined -> True, GridLines -> Automatic, > PlotRange -> {{1, 3}, {0.5, 1.5}}, PlotRangeClipping -> False, > ImagePadding -> 10] Actually, the problem with using Disk[] (or Point[]) is that they are much slower than the default. Try to run: ListPlot[Range[1000], PlotMarkers -> {Graphics[Disk[]], 0.02}] Compare it with: ListPlot[Range[1000]] And if you try to use Range[10000], you will see another difference. Of course, that's a very large number of points, I don't need this in practice, but I need to optimize the speed. Actually, I need to plot several functions on the same plot, some of which with points shown, some of them only as joined lines. I think, that I need to use Show to implement this correctly. Didn't yet try to measure speed of this function..