Damien,
Presumably the math model in MapInfo is a "Kosher" Lambert Conformal Conic and
is fully conformal. Therefore, it is acceptable for use in El Salvador. Note,
however, it is NOT suitable for use in France for coordinates determined prior
to 1948. That is the year the country of France changed from the old French
Army Truncated Cubic math model to the fully conformal math model which is
probably in MapInfo.
Beware of working in areas and countries that used to be French Colonies. With
the exception of "new" stuff in Algeria (they changed the math model in the 70's
or 80's I think), ALL other foreign French Stuff is the old Truncated Cubic if
it is on the Lambert. (Of course, many other projections have been used also by
the French for large-scale topo and hydro work.)
Don't forget that El Salvador uses one zone but it has two Datums. (Ocotepecque
Datum of 1935 and NAD 1927.) See my column from July 1999 in "Photogrammetric
Engineering and Remote Sensing, or you can download the paper (about neighboring
Honduras), under Grids and Datums stuff from:
http://www.asprs.org/resources.html
--
Clifford J. Mugnier ([EMAIL PROTECTED])
The Topographic Engineering Laboratory
Department of Civil and Environmental Engineering
UNIVERSITY OF NEW ORLEANS
New Orleans, Louisiana 70148
Voice: (504) 280-7095
Facsimile: (504) 286-1200
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Damien CHAMINADE wrote:
>
> I work with data from Salvador. The used projection is Lambert.
>
> I have modified the file MapInfow.prj accorded to the parmeters got in the
> National Institute delaing with geographical data. There are correct.
>
> 1) I would like to know wether the Lambert defined in MapInfo is only
> correct for France, or it may be used for any country.
>
> 2) Is there anybody who has already worked with data from Salvador?
>
> Thanks,
>
> D. Chaminade
>
> ----------------------------------------------------------------------
>
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