[Kst] Image data type

Barth Netterfield netterfield at astro.utoronto.ca
Wed Jul 21 19:53:03 CEST 2004

Comments to this, and to other traffic on this topic...

-I thought I sent out an email about 3d plotting a month or so ago, but I 
can't find it.  Did I? Have you looked at it?  

Sumary from memory:

Data Types:
-'Images' are function surfaces.  They might be represented in two ways:
	i) Z(x0 + i*dx, y0 + j*dy) (ie, in a regular grid)
	ii) Z(x[i], y[i]) (ie, 3 vectors not necessarily on a grid)
Supporting (ii) from the file level will be very handy, but requires some sort 
of binning policy.  (i) is easy and relatively policy free, but not as 

I can think of three main ways to show an 'image':
	(i) Color map (as noted, 24 bits are probably required)
	(ii) contour plot
	(iii) rotatable surface plot

(i) and (ii) are both 2D objects and could/should be plotted in a kst2d plot, 
because they share the same zoom actions, and could naturally be expected to 
be plotted beneath regular curves.  I agree that they should be connected to 
kst2dplot as an analog to curves.
(iii) is a 3d object which will be presented in kst3d plot.

I am *very* hesitant to start down this path now.  There is a lot to consider 
and get right, and I would much rather have us focusing on a high quality 1.0 
release!  But.... if you are sure you can do this without jeprodizing 1.0.... 
perhaps (gulp!)  Can you have something mainly working in 1 week?

On July 20, 2004 02:00 pm, Rick Chern wrote:
> I am currently working on an Image data type.  Description of images:
> - images will be specified by three vectors, representing x, y, and z

So you intend to support un-gridded data.... What is your binning policy going 
to be?  What do you do about over-sampled maps?  about undersampled maps?  
How will you decide on gid density?

> - it is up to the user to make sure the three vectors selected make
> sense as an image

What does this mean?

> - images will be plotted on the 2D plot, using colours/shades to represent
> z - only 1 image can be plotted per plot

What will the colour-scale interface be?  Also, one might want to show 
multiple images covering different parts of the XY space, or to have a colour 
map under a contour plot.  So I wouldn't limit to one image per plot.

> - images will be plotted underneath any curves


> - images will appear as new data objects in the data manager


> Changes I would make:
> - create a KstImage class inheriting from KstDataObject (not KstBaseCurve)
> - add Image button to the New section of data manager
> - modify plot dialog slightly to be able to select 1 image (or not)
or more than one?  I would just list the images with the curves.

> - create an image New/Edit dialog

> - make changes to Kst2DPlot to set, remove, and plot the image, if the
> plot has one


> I just wanted to check to be aware of any problems before I went to far
> - some of the changes have been made, but not committed yet.

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