Re: [Gnuplot-info] keyword using with binary data matrix

[Edmond R. <ero...@gm...>]

Thank you.   dx is not quite what I was looking for.

I wish do do something like:
plot "file" binary array=18000x4500 flipy format='%int16  using
(($1/50.0)-180):(($2/50.0)-90):3 ...........

But I can only do that if I am reading an ascii matrix, but not with a binary.

It is just that making the ascii files takes time and space, but the
real issue is how long gnuplot spends reading and plotting a large
ascii file.  The binary is much faster.

There are options such as x2range and y2range, but I preferred
manipulating the index values
On Thu, Sep 27, 2018 at 7:28 PM Ethan A Merritt <eam...@gm...> wrote:
>
> On Thursday, 27 September 2018 16:56:53 Edmond Rodriguez wrote:
> > So I can read a matrix of binary data and make an image plot like this:
> >
> > plot "file" binary array=18000x4500 flipy format='%int16' with image
> >
> > But I want to manipulate the points with using keyword.
>
> Gnuplot does not support that.
>
>
> > But I cannot.
> >
> > So I have to do this:
> >
> > dump the binary file to ascii:
> > od -v -An -t d2 -w36000 file | tac > file.asc
> >
> > Then I can plot:
> > plot 'file.asc' matrix using 1:2:3 with image palette
> > or change values:
> > plot 'file.asc' matrix using ($1/50):2:3 with image palette
> >
> > How do I accomplish the "using" in the binary method
> >
> > The reason I want to do this is so I can do math  on the numbers.
> >
> >  I want to do something like this but I am not getting it right:
> >
> > plot "file" binary array=18000x4500 flipy format='%int16'  using
> > ($1/50):2:3 with image
>
> I take it that what you want is to shrink the range of x coordinate
> occupied by the image.  There is a keyword for that
>   plot "file" binary array=18000x4500 dx=0.02 dy=1.0 ...
>
> For examples see
>   http://gnuplot.sourceforge.net/demo_5.3/barchart_art.html