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Re: splotting with pointsize variable => huge points!!!

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sfeam wrote:

> gvdmoort wrote:
> 
>> On 7 juin, 01:43, sfeam <sf...@users.sourceforge.net> wrote:
>> 
>>> I am guessing that you really were aiming for a 2D plot?
>>> In that case the command you want is
>>>
>>> gnuplot> plot '-' matrix using 1:2:3 with points pt 7 ps variable
>>>
>> 
>> Thanks for your reaction. There was some confusion in my 1rst message
>> because I also tried to plot data from an image to points with
>> variable size.
>> 
>> This doesn't work:
>> 
>> gnuplot> plot 'grey_small.png' binary filetype=auto using 1:2:($3/255)
>> with points pt 7 ps variable
>>          Too many using specs for this style
> 
> 
> Hold on a moment.
> Originally you were asking about ascii input data -
> how does this PNG file fit into the picture?
> 
> It would help if you would explain what you are trying to do.
> Is the idea to map the pixel value into a point size?  Why?
> What is the mapping?  Are you sure you want a PNG file for this?
> 
> The input mode "binary filetype=png"  (you used "auto" but that's the same
> since it's a png image) is only intended for use with the image plot
> styles (with image, with rgbalpha, etc).  But "set table" doesn't know how
> to dump image data, so I suspect you're just plotting garbage at that
> point.

Note: 
If you really want to dump the RGBAlpha values from a PNG file in gnuplot,
you can mis-use a different 6-column plot mode:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
gnuplot>   set table
gnuplot>   plot 'bldg.png' binary filetype=png with xyerrorbar

# Curve 0 of 1, 6527 points
# Curve title: "'bldg.png' binary filetype=png"
# x y xlow xhigh ylow yhigh type
 0  127  255  255  255  255  i
 1  127  255  255  255  255  i
     ... and so on ...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Although "set table" labels the columns xlow/xhigh/ylow/yhigh
in this case they are really  Red/Green/Blue/Alpha

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splotting with pointsize variable => huge points!!! gvdmoort <gvdmoort@skynet.be> - 2012-06-06 02:27 -0700
  Re: splotting with pointsize variable => huge points!!! sfeam <sfeam@users.sourceforge.net> - 2012-06-06 16:43 -0700
    Re: splotting with pointsize variable => huge points!!! gvdmoort <gvdmoort@skynet.be> - 2012-06-07 12:16 -0700
      Re: splotting with pointsize variable => huge points!!! sfeam <sfeam@users.sourceforge.net> - 2012-06-07 14:12 -0700
        Re: splotting with pointsize variable => huge points!!! sfeam <sfeam@users.sourceforge.net> - 2012-06-07 14:27 -0700
        Re: splotting with pointsize variable => huge points!!! gvdmoort <gvdmoort@skynet.be> - 2012-06-08 00:10 -0700
        Re: splotting with pointsize variable => huge points!!! gvdmoort <gvdmoort@skynet.be> - 2012-06-08 00:22 -0700

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