<html><head><base href="x-msg://50/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Hi Paul,</div><div><br></div><div>This calculation includes an ellipticity correction and the latitudes are assumed to be geographic.</div><div><br></div><div>We are considering the idea of adding the calculated distance assuming geocentric coordinates to the service. This would allow users to supply coordinates in either convention.</div><div><br></div><div>regards,</div><div>Chad</div><br><div><div>On Nov 16, 2011, at 4:20 AM, Denton, Paul wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-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: 0px; font-size: medium; "><div><font face="Calibri, sans-serif" size="2"><div>Does anyone know what earth model the distaz webservice uses to calculate distances (all I can tell is that it appears not to be a spherical earth model)</div><div> </div><div>Thanks</div><div> </div><div>Paul Denton</div><div>UK school seismology project leader</div><div>British Geological Survey</div><div>Keyworth</div><div>Nottingham NG12 5GG</div><div>email<span class="Apple-converted-space"> </span><a href="mailto:pdenton@bgs.ac.uk">pdenton@bgs.ac.uk</a></div><div>web <span class="Apple-converted-space"> </span><a href="http://www.bgs.ac.uk/ssp">www.bgs.ac.uk/ssp</a></div><div> </div><div> </div><div> </div></font><br>--<span class="Apple-converted-space"> </span><br>This message (and any attachments) is for the recipient only. NERC<span class="Apple-converted-space"> </span><br>is subject to the Freedom of Information Act 2000 and the contents<span class="Apple-converted-space"> </span><br>of this email and any reply you make may be disclosed by NERC unless<span class="Apple-converted-space"> </span><br>it is exempt from release under the Act. Any material supplied to<span class="Apple-converted-space"> </span><br>NERC may be stored in an electronic records management system. _______________________________________________<br>webservices mailing list<br><a href="mailto:webservices@iris.washington.edu">webservices@iris.washington.edu</a><br><a href="http://www.iris.washington.edu/mailman/listinfo/webservices">http://www.iris.washington.edu/mailman/listinfo/webservices</a><br></div></span></blockquote></div><br></body></html>