<html><body name="Mail Message Editor"><br>On Jan 9, 2009, at 8:52:48 AM, OvV_HN <ovv@hetnet.nl> wrote:<br><blockquote style="padding-left: 5px; margin-left: 5px; border-left-width: 2px; border-left-style: solid; border-left-color: blue; color: blue; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: -webkit-monospace; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; ">> On the subject of the transverse Mercator projection, I'm about 2 weeks<br>> away from posting a new version of my "exact" TM program with much more<br>> exhaustive testing (see above), a more careful treatment of singular<br>> points, etc. Stay tuned.<br><br>Nice!<br>I've already resolved the lat=90d problem in the inverse (calculation of<span class="Apple-converted-space"> </span><br>zeta where snv==0 and (cnu==0 or dnv==0) ), but there are probably some more<span class="Apple-converted-space"> </span><br>problems? I'll stay tuned!<br><br>Oscar van Vlijmen<br></span></blockquote><div><br></div>I find the regions from the cusps to a short way along the outer boundary, just inside the boundary, to be most computationally problematic. However, I am not using Thompson/Lee's development through Jacobian elliptic functions, so possibly your difficult terrain differs. I do not use Jacobian elliptic functions at all; only an elliptic integral of the second kind. I am satisfied with my results throughout the rest of the map, so I am keen to compare notes in case it makes sense to bring both methods to bear, depending on the region.<div><br></div><div>Regards,</div><div>— daan Strebe</div><div><div><br></div></div><div class="aol_ad_footer" id="u507E5B330937451790649636AA18BB08"></div></body></html>