Scripts written while developing the Sloan Galaxies exhibit

redshift2dist.m. Matlab function to convert redshift to distance (comoving coordinates). Accurate to within a few megaparsecs of Ned Wright's Cosmology Calculator for z < 10. Fast - processes 250 000 redshifts in under 10 seconds on a PC bought in 2002.

radecz2xxyyzz.m. Matlab function to convert ra/dec/redshift to x/y/z coordinates. It also returns distance from the origin. It calls redshift2dist.m above and uses the conversion

  z=r*cos(90-dec) ;

addcoarsecol.m. Matlab function that bins a column of a matrix into an arbitrary number of bins. See documentation in file for explanation. It was written for this purpose: each galaxy from the Sloan Digital Sky Survey came with a eClass value. We wanted to place the galaxies in N (=10) 'bins' depending on their eClass value, and store for each galaxy the number of the bin its in. Later, all galaxies in the same bin are given the same picture.

randompolyori.m. Matlab function that creates N random polygon orientations in Partiview format. Perl script that replaces the commas in a comma-separated file by spaces. Matlab can read the resulting file. Perl script that splits a big .speck file into lots of .speck files, each of which has a single texture. Also revamps the .cf file that goes with it. Perl script example for testing if something is a number or not... works as tested (see main function in this script), not tested very hard, use at your own risk. I'd bet your life on it, not mine.