Re: Flat colour in RegionPlot; millions of little triangles
- To: mathgroup at smc.vnet.net
- Subject: [mg81712] Re: Flat colour in RegionPlot; millions of little triangles
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Tue, 2 Oct 2007 05:32:59 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <fdkqst$7bk$1@smc.vnet.net> <46FDF56B.5070106@gmail.com> <fdl9e7$d1p$1@smc.vnet.net>
Will Robertson wrote:
> Hi Jean-Marc,
>
> Thanks for the reply.
>
> On 29/09/2007, at 16:19 , Jean-Marc Gulliet wrote:
>> Could you be more precise about the size of the exported files
>> (before and after manual fixing) and about what size you expect and =
>
>> deem as reasonable?
>
> Sure, the example I posted is not particularly large or complex (but
> it does demonstrate the problem). When calculating RegionPlot with a
> troublesome function that requires a very tight mesh, however, the
> problem is much worse. (Displaying the PDF in Acrobat Reader is
> visibly delayed as it stops to draw every single blue polygon.)
>
> I can't test out a more complicated example until I get back to my
> office but you might find that this produces a more troublesome PDF:
> ContourPlot[Sin[x y],{x,=E2=88=925,5},{y,=E2=88=925,5}]
Hi Will,
In version 6, the quality of a plot depends on the value of some new
options such as *MaxRecursion* (my understanding is that this option
controls the behavior of the new adaptative sampling algorithm) and also
*PlotPoints*.
Below you will find sizes of pdf files created from *ContourPlot* with
various settings of *MaxRecursion* and *PlotPoints*.
Using the default values, we can see that the pdf file is about 1.5 Mb,
whereas, setting *MaxRecursion* to 0, the size is about 72 Kb, i.e 21
times less.
Now, look at the quality (aesthetic) of the graph in both cases: the
differences ares striking and the visual appearance of the former graph
is so poor that it looks like it has not been produced by the same
application (at least to my eyes :-)
You can find the evaluated notebook and a pdf version at
http://homepages.nyu.edu/~jmg336/mathematica/contour-plot.pdf
http://homepages.nyu.edu/~jmg336/mathematica/contour-plot.nb
In[1]:= $Version
Out[1]= "6.0 for Microsoft Windows (32-bit) (June 19, 2007)"
In[2]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
PlotLabel -> "MaxRecursion->Automatic\nPlotPoins->Automatic"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[4]= 1535524
In[5]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 0,
PlotLabel -> "MaxRecursion->0\nPlotPoins->Automatic"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[7]= 72915
In[8]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 1,
PlotLabel -> "MaxRecursion->0\nPlotPoins->Automatic"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[10]= 321697
In[11]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 2,
PlotLabel -> "MaxRecursion->2\nPlotPoins->Automatic"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[13]= 1535522
In[14]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 2, PlotPoints -> 5,
PlotLabel -> "MaxRecursion->2\nPlotPoins->5"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[16]= 214543
In[17]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 2, PlotPoints -> 6,
PlotLabel -> "MaxRecursion->2\nPlotPoins->6"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[19]= 509790
In[20]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 2, PlotPoints -> 7,
PlotLabel -> "MaxRecursion->2\nPlotPoins->7"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[22]= 602774
In[23]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5},
MaxRecursion -> 2, PlotPoints -> 10,
PlotLabel -> "MaxRecursion->2\nPlotPoins->10"]
Export["contour-plot.pdf", %];
ByteCount /. FileInformation[%]
Out[25]= 905323
Regards,
--
Jean-Marc