Bill,
Many thanks for the info.
Maybe Mapinfo could provide online access on more background information on
projection systems that are not pre-set in the mapinfow.prj file.
Thanks
[EMAIL PROTECTED] wrote:
> from our online knowledgebase on www.mapinfo.com:
> Background:
>
> Excerpt from John Snyder's "Map Projections-A Working Manual":
>
> This projection appears to be used simply for ease in plotting. The USGS
> distributes maps in this projection that are not marked with the projection
> name or scale to avoid implying the maps are suitable for geographic
> information.
>
> The Hotline Oblique Mercator appears to be one of its more modern forms and
> is used more often presently.
>
> Question:
>
> Is this the same as a simple Longitude\Latitude (no datum) projection with
> an affine transformation such as a Plane Chart?
>
> >From MapInfo-L 9/15/98: Thanks to the unnamed contributor.
>
> The Plate Carre projection, also known as the Equidistant Cylindrical
> Projection, is equivalent to a MapInfo's "Longitude\Latitude
> projection" with an affine transformation. Try this coordinate
> system:
>
> Coordsys Earth Projection 1,0 Affine units "m", 111200,0,0,0,111200,0
>
> Or, in the MAPINFOW.PRJ file:
>
> "Longitude\Latitude Plate Carre Projection", 3001, 0, 7,
> 111200,0,0,0,111200,0
>
> To get the correct coordinate values, specify the number of coordinate
> units in a degree instead of the 1's.
>
> For example, the very rough estimate of 111,200 meters in a degree yields
> the following CoordSys clause:
>
> Coordsys Earth Projection 1,0 Affine units "m", 111200,0,0,0,111200,0
>
> This example gives suitable results at a world-wide scale.
>
> If this is a raster map, let the raster registration process take care of
> all the factors that appear below.
>
> If it's a vector map, users will have to deal with the following factors in
> order to get maps to line up correctly with datasets in
> other projections:
>
> "The Earth's equatorial bulge is represented by giving the y scaling factor
> (the second 111200) a slightly smaller value from the x scaling factor (the
> first 112000). The ratio of the two numbers is a function of the
> eccentricity of the spheroid in the datum being used (It is probably
> sqrt(1-e^2)), but needs to be verified).
>
> Finally, the origin of the coordinate system may not be the intersection of
> the Meridian of Greenwich and the Equator.
>
> The projection's "False Easting" is the third number in the affine
> transformation, the "False Northing" is the sixth number.
>
> It appears to line up nicely with same maps in simple Longitude\Latitude
> projection, no affine specs.
>
> Mail List:owner-mapinfo-l
>
> From: Max Fernandez <[EMAIL PROTECTED]>
> on 05/30/2000 07:19 PM ZE2
>
>
> To: Martin Emch <[EMAIL PROTECTED]>
>
> cc: MapInfo-L Mailing List
> <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
>
> Subject: (Document link: MapInfo -L and Co.)Re:
> MI Space oblique Mercator ???
>
>
> I have a similar problem but with another projection:
> where do I find / or how do I create the settings in mapinfow.prj for a
> "plate
> carr�e" ("flat square") projection
>
> TAI
> Max
>
> Martin Emch wrote:
>
> > I have several pictures in the projection above, which setting should i
> do
> > in Mapinfo?
> >
> > Thanks Martin
> >
> > ----------------------------------------------------------------------
> > To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put
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>
> --
> *********************************************************************
> Max Fernandez
>
> Departement Geologie, Koninklijk Museum voor Midden - Africa
>
> D�partement de G�ologie, Mus�e royal de l'Afrique centrale
> Department of Geology, Royal Museum for Central Africa
>
> Steenweg op Leuven, 13 tl: +32 2 769 5431
> B-3080 Tervuren fx: +32 2 769 5432
> Belgium email: [EMAIL PROTECTED]
> *********************************************************************
>
> ----------------------------------------------------------------------
> To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put
> "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
--
*********************************************************************
Max Fernandez
Departement Geologie, Koninklijk Museum voor Midden - Africa
D�partement de G�ologie, Mus�e royal de l'Afrique centrale
Department of Geology, Royal Museum for Central Africa
Steenweg op Leuven, 13 tl: +32 2 769 5431
B-3080 Tervuren fx: +32 2 769 5432
Belgium email: [EMAIL PROTECTED]
*********************************************************************
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To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put
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