Cassini cylindrical projection

This cylindrical projection was developed in 1745 by César-François Cassini de Thury for the survey of France. It is occasionally called Cassini-Soldner since the latter provided the more accurate mathematical analysis that led to the development of the ellipsoidal formulae. The projection is neither conformal nor equal-area, and behaves as a compromise between the two end-members. The distortion is zero along the central meridian. It is best suited for mapping regions of north-south extent. The central meridian, each meridian 90° away, and equator are straight lines; all other meridians and parallels are complex curves.

clon0/lat0/scale or Clon0/lat0/width

The projection is set with c or C. The projection center is set by lon0/lat0, and the figure size is set with scale or width.

import pygmt
from pygmt.params import Axis

fig = pygmt.Figure()
# Use the ISO code for Madagascar (MG) and pad it by 2 degrees (+R2)
fig.coast(
    region="MG+R2",
    projection="C47/-19/12c",
    frame=Axis(annot=True, tick=True, grid=True),
    land="gray80",
    water="steelblue",
)
fig.show()