[OSRS-PROJ] Goode projection discrepancy

Gerald I. Evenden gevenden at capecod.net
Fri Oct 6 10:25:45 EDT 2000


Defining interrupted projections within PROJ is *not* in the spirit of
PROJ's
purpose nor scope.  PROJ was designed to provide a computation system
to solve the mathematical aspects of cartographic projections.

Doing an interrupted projection is a graphical problem involving the
windowing
and control of where elements are placed in a complex. manner.
The mathematical part (PROJ's work) is secondary and relatively trivial.

In addition, interrupted projections often suffer from a variety of forms
and individual interpretation of the atlas builder.  For example, Goode has
a land weighted version (most common) *and* an oceanic weighted
version.

To add interruption methods into the PROJ system destroys its modularity
and confuses graphical operations with the mathematic definitions.  PROJ is
*not* a map making system, it is a system to compute the transformations
between geographic and Cartesian space.

Interestingly, when I made interrupted maps, having the interruptions inside
the
projections would have made designing the mapping software almost
impossible.
The regional outlines had to be available for the clipping procedures so
there was
no advantage to include them in the projection.

Lastly, to answer the question posed, yes a new Y offset has to be computed
if the boundary latitude is changed.

__________________________________________________
Jerry Evenden and the Low Riders, Katie and  Daisy May
gevenden at capecod.net  http://www.capecod.net/~gevenden

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