CT_HotineObliqueMercatorAzimuthCenter added .. new CT_ policy

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CT_HotineObliqueMercatorAzimuthCenter added .. new CT_ policy

Frank Warmerdam
Folks,

At the point when GeoTIFF was created EPSG (apparently) did not have
an enumeration for coordinate transformation methods (like Transverse
Mercator).  So the GeoTIFF spec embedded it's own - the CT_*
constants in geo_ctrans.inc.

Shortly after that EPSG added the coordinate_operation_method
table but the split had already occured.  Since EPSG has added many
projection methods not included in GeoTIFF.   It looks like I, by fiat,
added CT_CylindricalEqualArea and perhaps CT_TransvMercator_SouthOrientated
with consecutive codes.  However, this did not do much to catch things
up with EPSG.

I have recently done a bunch of work in GDAL to differentiate
EPSG's hotine oblique mercator methods, marking 9815
as distinct with a name of Hotine_Oblique_Mercator_Azimuth_Center.
I was going to add it to GeoTIFF too but I really don't want to have
distinct codes between EPSG and GeoTIFF.  So I am suggesting
(and implementing) a move to using the EPSG transform codes for
new projection methods.

Are there there any questions or concerns about this?

eg.

in geo_ctrans.inc:

/* Added May 2012 - from now on we use the EPSG */
ValuePair(CT_HotineObliqueMercatorAzimuthCenter, 9815)


Best regards,
--
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, [hidden email]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Software Developer
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