What are the strengths and weaknesses of these projections?
There could be no listing of map projections in Cartography, sans
reference to the elliptical (19th century ) Mollweide projection. , for
both the (poles inclusive ) hemispheres, over an ellipse.
The semi of the ellipse are in the proportion a = 2b.
in appropriate scale (say
no distortion for the equatorial circle of length
Alternately, we can make the total surface area
represented. Here, area of the ellipse
The 20th century A. H. Robinson.s map is similar, with the
weaknesses that it is neither conformal ( in preserving surface
angles ) nor keeping local areas on the same scale. The strength is
in Meredian ( longitudinal ) great circles turning gently towards
poles. In my opinion, Mollweide's projection is a basis for National
Geographical Society (NGS)-supported Robinson projection.
Oldest is G. Mercator's cylindrical map for the globe. When spread
over a Table, it is rectangular. We cannot map polar regions here,
The scale distortion is
is the forerunner for all the subsequent improvements.
I break here, to continue after some hours, in my next edition of
Mercator's map preserves the stretch along the equator.. As
latitude increases, lengths are zoomed. In other words, the
Scandinavian countries would be very much stretched. Using
this, we could easily make out finer details for places over
higher-latitude small circles
.The projection contributed by J. Galli and A. Peter in in 20th
century was adopted in British schools. It is cylindrical equal-area
projection and is better for sub polar latitudes. The area for USA
will be thrice the area for India. The ratio is preserved.
In equidistant maps , each location is dragged relative to the
other so that the distance scale is preserved. This is good with
respect to instant location, for relative distances.
Azimuthal circular projection .is centered at a pole and is good if it
ends with the equator great circle. Locations with same longitude
lie on a radius, Latitude circles are really small. The globe can be
presented separately in two circular maps, for the northern and
southern latitudes, respectively.
Despite relative merits, all are good and meticulous. for local (
spherical cap ) neighborhood, .
For graphical depictions, see respective wiki pages, for these