[Proj] proj4 definition for transverse mercator projection from RegCM3 model for North America

[Melita Kennedy]

-----Original Message-----

>Date: Sat, 24 Jul 2010 00:52:37 +0300 (EEST)
>From: support.mn at elisanet.fi
>Subject: Re: [Proj] proj4 definition for transverse mercator
>	projection from RegCM3 model for North America
>To: "PROJ.4 and general Projections Discussions"
>	<proj at lists.maptools.org>
>
>Hello,
>
>> The sphere ellipsoid is a guess as they didn't provide the geographic coordinate system
>
>check your parameters, especially if the assumption about the sphere is correct and if the
>sphere is of a right size? Test with the normal NAD83, NAD27, WGS84 datums with their
>correct ellipsoids Clarke 1866,  GRS 80 and WGS84 etx.
>
>http://en.wikipedia.org/wiki/North_American_Datum
>
>http://en.wikipedia.org/wiki/World_Geodetic_System
>
>Janne.

I just looked through some of the RegCM3 source code. I did find a 6371229.0 value in the projection section of terrain.f. It doesn't list transverse Mercator as an option, rather it's a rotated (oblique) Mercator. The equations for this and the other projections are definitely sphere-based with no sign that the incoming terrain data (ex. USGS LULC) is being converted from the ellipsoid-based datum to the sphere. 

Melita

Melita