[OSRS-PROJ] NTv1 (Canadian) Grid Shifts, and proj_def.dat

Craig Bruce csbruce at cubewerx.com
Thu Apr 5 15:57:45 EDT 2001

Frank Warmerdam <warmerdam at pobox.com> wrote:

> Second, I would like to change proj_def.dat to provide a default ellipsoid
> of WGS84 (really would make it +datum=WGS84).  The assumption is that in
> this day and age WGS84 is a better default than clrk66 (normally NAD27).
> What are peoples opinions on making this change?  Obviously it could
> cause some problems, but I have been bitten a number of times by the
> implicit appending of clrk66.

It sounds good to me.  However, I think that the documentation should
clearly say that the implicit datum is subject from change from time
to time and that any software system interfacing with the PROJ library
or any scripts or configurations which rely on a specific default datum
and which are likely to stay around for a while should use an explicitly
named datum.  Using the implicit datum is for quick-and-dirty work only.

Dr. Craig S. Bruce        | Ph.: 819-771-8303 x205 |             CubeWerx Inc.
Senior Software Developer |   Fax: 819-771-8388    |      Hull, Québec, Canada
csbruce at cubewerx.com      | http://www.csbruce.com |  http://www.cubewerx.com/
                     "A stuffed penguin on every desktop."
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