<HTML dir=ltr><HEAD><TITLE>Re: [Proj] Some typos in the libproj4 manual</TITLE>
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<DIV dir=ltr><FONT face="Times New Roman" color=#000000 size=2>The statement, "By stating that 2 decimals are more than enough, because we don't do<BR>nothing below the centimeter level" is incorrect.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>In the United States, for the legally-defined State Plane Coordinate Systems, the controlling document for algorithms and computational precision is NOAA Manual NOS NGS 5 by James E. Stem. That is the <EM>official </EM>document. It can be downloaded in a pdf file from <A href="http://www.ngs.noaa.gov/PUBS_LIB/ManualNOSNGS5.pdf">http://www.ngs.noaa.gov/PUBS_LIB/ManualNOSNGS5.pdf</A> </FONT></DIV>
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<DIV dir=ltr><FONT size=2>In that document, the requirement is for computational accuracy to the tenth of a millimeter (0.0001 meters).</FONT></DIV>
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<DIV dir=ltr><FONT size=2>That is not getting carried away, it <STRONG><U>is</U></STRONG> complying with a National Specification.</FONT></DIV>
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<DIV dir=ltr><FONT size=2>Cliff Mugnier</FONT></DIV>
<DIV dir=ltr><FONT face="Times New Roman" color=#000000 size=2>LOUISIANA STATE UNIVERSITY<BR></FONT><BR>
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<FONT face=Tahoma size=2><B>From:</B> proj-bounces@lists.maptools.org on behalf of OvV_HN<BR><B>Sent:</B> Thu 02-Oct-08 04:09<BR><B>To:</B> PROJ.4 and general Projections Discussions<BR><B>Subject:</B> Re: [Proj] Some typos in the libproj4 manual<BR></FONT><BR></DIV></DIV>
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<P><FONT size=2>----- Original Message -----<BR>From: "Gerald I. Evenden" <geraldi.evenden@gmail.com><BR>Sent: Wednesday, October 01, 2008 10:55 PM<BR>Subject: Re: [Proj] Some typos in the libproj4 manual<BR><BR>....<BR>>> problems in the manual.<BR>....<BR>> I will put the current version on my site by this weekend. Some<BR>> corrections<BR>> may have escaped due to my occasional sloth. My apologies in advance.<BR><BR>Thanks!<BR><BR><BR>>> Another suggestion: give a numerical example with at least 5 decimals<BR>>> plus<BR>>> the exact command line code for each and every function.<BR>> What do you mean by "every function." In term of precision of functions<BR>> that depends upon what the function is returning.<BR>....<BR>> On occasion, I think some get a little carried away with precision. ;-)<BR><BR>Working at the nanometer level has absolutely no significance for geodesy.<BR>That part we do agree upon.<BR>But look for instance at the test files in the GNU GSL distribution.<BR>One has to be able to check the correct functioning of all available<BR>functions in all relevant or in all supported regions.<BR><BR>It would be nice to give some real world examples, using parameters of<BR>actually used projections, but exactly at that moment some people will drift<BR>off from the intents of a test example.<BR>How? By stating that 2 decimals are more than enough, because we don't do<BR>nothing below the centimeter level.<BR><BR>What is needed are abstract examples or real world examples, just examples,<BR>with a lot of decimals, so that the user can check whether his compile, his<BR>microprocessor, his porting, his whatever, are done perfectly.<BR><BR>Please allow me to repeat:<BR>One has to be able to check the correct functioning of all available<BR>functions in all relevant or in all supported regions.<BR><BR><BR>Oscar van Vlijmen<BR><BR></FONT></P></DIV></BODY></HTML>