<div dir="ltr"><div><div><div><div>Duncan,<br><br></div>We have been through a morass with oblique mercator and it's different forms over recent years, and I'm afraid I don't recall all the details. There is some discussion at:<br>
<br> <a href="http://trac.osgeo.org/proj/ticket/104">http://trac.osgeo.org/proj/ticket/104</a><br><br></div>I observe that you get the old results if the +no_rot flag is omitted:<br><br>invproj +proj=omerc +lat_0=33 +lonc=-116 +alpha=45 +ellps=WGS84<br>
0 0<br>116dW 33dN<br><br></div>I think at least part of the issue had to do with where the +no_rot flag was interpreted relative to but I'm not inclined to investigate deeply. Ticket #104 has points to some other tickets that might help.<br>
<br></div>It might be nice for us to prepare an FAQ entry explaining the changes and when they came into effect if someone can summarize simply.<br><br>Best regards,<br><div>Frank<br><br></div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Fri, Sep 6, 2013 at 3:58 PM, Duncan Agnew <span dir="ltr"><<a href="mailto:agnew@cahuilla.ucsd.edu" target="_blank">agnew@cahuilla.ucsd.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Under proj 4.7.1, if I input 0 0 to<br>
<br>
invproj +proj=omerc +no_rot +lat_0=33 +lonc=-116 +alpha=45 +ellps=WGS84<br>
<br>
I get 116dW 33dN as output. However, doing the same for proj4.8.0<br>
gives<br>
<br>
144d29'13.013"W 0d4'39.96"S<br>
<br>
I've been using proj for some time; this has me baffled. (I should note<br>
that the inverse and forward are consistent in both versions).<br>
<br>
proj 4.7.1 was installed on Mac OSX 10.5, 4.8.0 on MacOSX 10.8<br>
installed from MacPorts<br>
<br>
Thanks<br>
<span class="HOEnZb"><font color="#888888">Duncan Agnew<br>
<a href="mailto:dagnew@ucsd.edu">dagnew@ucsd.edu</a><br>
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</font></span></blockquote></div><br><br clear="all"><br>-- <br>---------------------------------------+--------------------------------------<br>I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com" target="_blank">warmerdam@pobox.com</a><br>
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