[Kst] kdeextragear-2/kst/kst

Barth Netterfield netterfield at astro.utoronto.ca
Wed Apr 28 04:04:33 CEST 2004


We need to think about this mapping stuff for a moment (which I actually have 
for a couple years now...)

There are several ways to imagine '3d' data...

A) Data on a regular grid, expressed as an array.
	(imagine 'kst -z 1 -nx 200 -ny 200 array.dat')
B) Data as a list of (x,y,z) points (as 3 arrays)  
	(imagine 'kst -x 1 -y 2 -z 3 map.dat')
C) Data as a list of points, with an implicit pixel index (eg, healpix)
	(imagine 'kst -z 1 healpixmap.fits')
D) various representations of surfaces which are not functions (eg, the 
surface of a sphere)
	(don't imagine anything - we're not going here!)

I suggest that we implement support for A and B at the data type level:

A): kstarray which takes:
	vector, nx, ny, minx, miny 
and outputs:
	nx by ny array. 

B) kstTriLinearArray which takes:
	vector X, vector Y, vector Z, nxpix, nypix, 
and outputs 
	a trilinear interpolated nx by ny array from Xmax to Xmin and Ymax to Ymin.

C) could be a data source converted type...  or do we want a KstHealPixArray?

To the plot classes, both arrays appear the same.


There are two main classes of presentation of the data: 
 1) flat maps: (ie, pixel maps, contour plots)
 2) 3d images (ie, isometric plots, rendered surfaces...)

Class (1) does not need or benifit from openGL, and there is no concept of 
rotation.  These are fundamentally 2d objects + 'color'.  They would mainly 
have the same interface as the 2dplots currently do, but with, an eg, 
colormap entry and 'show pixels' and 'show contours' and 'contour interval' 
options in various places (the rmb menu and various dialogs.)

Class (2) are openGL type objects, and will need a hightly modified mouse 
interface, etc.

I suggest we do (1) now (kstmap) and leave (2) (kst3dplot) for later.

Andrew, do you want to create the data types so Ted can start on the healpix 
data source?


On April 27, 2004 04:44 pm, Ted Kisner wrote:
> On Tuesday 27 April 2004 16:23, Andrew Walker wrote:
> > Added 3d-plotting class
> very cool.  Is there a plan yet for what kind of 3D library will be used? 
> Or will every type of 3D view (pixel map, contour plot, isometric, etc) be
> written from scratch?  I guess there are pros and cons to both ways...
> -Ted
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