In the Graphics Interface '94 version of our paper, there was an error in the reference to Ihm and Naylor's work (ref [14] on pages 5 and 8). We earlier said that their dynamic programming algorithm for curve simplification had complexity O(m n^3) but it was, in fact, O(n^3 log m), and their paper did not appear in a 1993 book edited by Hagen, but in a 1991 book edited by Patrikalakis. These minor corrections have been made in the Postscript file available via WWW in this directory. -Paul Heckbert, 12 May 95