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On Thu, 2005-07-07 at 13:02 -0500, William K wrote:
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<FONT COLOR="#000000">On Jul 7, 2005, at 12:31 PM, Gerald I. Evenden wrote:</FONT>
<FONT COLOR="#000000">> First. "trillion" seems to have a ambiguous definition in Kdict so </FONT>
<FONT COLOR="#000000">> I am not sure about</FONT>
<FONT COLOR="#000000">> your what you mean here. Is it greater or lesser than a </FONT>
<FONT COLOR="#000000">> gazillion? :-) sorry about my humor.</FONT>
<FONT COLOR="#000000">></FONT>
<FONT COLOR="#000000">I think trillion is a standard thing - the next step beyond a </FONT>
<FONT COLOR="#000000">billion, 1,000,000,000,000.</FONT>
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<BR>
Perhaps it is. I've only seen reference to the number describing our US national debt---<BR>
far too large a value to comprehend. In practice here I prefer either the number or range<BR>
in powers of 10.<BR>
<BR>
Alas, the solution to the problem if you wish to fix your own copy of the source is to<BR>
remove the reference to the earth's radius in PJ_ocea.c. The first two executable<BR>
statements just after the entry ENTRY0(ocea) read<BR>
<BR>
P->rok = P->a / P->k0;<BR>
P->rtk = P->a * P->k0;<BR>
<BR>
Change the "P->a" to "1." on both lines. Simplify the second line if you like. I suspect<BR>
that this error has persisted over a long line of releases and versions and points to the<BR>
folly of using a unity earth radius as a test value (see p. 279, PP 1395). Also shows how<BR>
often ocea is used. This is such a dumb error. Only one projection references the<BR>
earth's radius (or major axis).<BR>
---<BR>
<BR>
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<FONT COLOR="#000000">'proj -le' lists all the ellipoids supported, and sphere is there </FONT>
<FONT COLOR="#000000">('Normal sphere', r=6370997). I have no seg faults with it. I get a </FONT>
<FONT COLOR="#000000">more graceful bail with unknown ellipsoids.</FONT>
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That is old PROJ4 stuff. Libproj4 does not list "sphere" as the value given is really only of interest<BR>
to NA users and a holdover from Snyder. The equivalent in more recent versions is<BR>
"+ellps=clrk66 +R_A" which generates a radius of a sphere with equivalent surface<BR>
area to the Clarke ellipsoid. See p. 7 of the Release 4 Interim Report. There are several<BR>
other variants of radius being derived from the ellipsoid that are described on page 7.<BR>
You can test the results with the -V option.<BR>
<BR>
---<BR>
<BR>
I have a handle on the error I was having which was related to error reporting by lproj.<BR>
I believe it is a problem with my inhouse version and will be fixed before the next release.
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--
_____________________________________________________________
Jerry and the Low Riders: Daisy Mae and Joshua
"The most certain test by which we judge whether a country is
really free is the amount of security enjoyed by minorities"
---Lord Acton, 1907
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