[Kst] RE: Kst Digest, Vol 12, Issue 32

Andrew Walker arwalker at sumusltd.com
Wed Apr 28 22:24:35 CEST 2004

I'll try to get to this on Monday, as I'll be away Thursday and Friday.



Date: Tue, 27 Apr 2004 22:04:33 -0400
From: Barth Netterfield <netterfield at astro.utoronto.ca>
Subject: Re: [Kst] kdeextragear-2/kst/kst
To: kisner at physics.ucsb.edu, kst at kde.org
Message-ID: <200404272204.33672.netterfield at astro.utoronto.ca>
Content-Type: text/plain;  charset="utf-8"


We need to think about this mapping stuff for a moment (which I actually
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

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?


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