User`s guide

R2006b
18-2
Standard Formulations of Five Major Map Projections
New formulations of five conic map projections are provided. The existing
implementations remain available under their old names. The new versions use the same
names as the ones they supplement, appended with “std”:
• Cassini Transverse Cylindrical (cassinistd)
• Albers Equal-Area Conic (eqaconicstd)
• Equidistant Conic (eqdconicstd)
• Lambert Conformal Conic (lambertstd)
• Polyconic (polyconstd)
Computations used for the new versions differ from the old ones only when the latitude
origin (the first element of the origin vector) is nonzero. In this case, the old versions shift
the origin off the equator through a solid body rotation of the sphere (or, for an ellipsoidal
earth model, a suitable auxiliary sphere). This is technically correct, but differs from
accepted industry standards for these projections. The new versions use the standard
formulations and give results that are consistent with projection results from other
software packages, regardless of the latitude origin. The old versions are retained in the
toolbox, with no change in behavior, to ensure backward compatibility.
See the Projections Reference documentation for more information.
Two New Geodetic/Geocentric Latitude Conversion Functions
Two new functions provide a more direct route to functionality already available via the
convertlat function:
• geocentric2geodeticlat converts an array of geocentric latitude in radians to
geodetic latitude in radians on a reference ellipsoid given a first eccentricity
• geodetic2geocentriclat converts an array of geodetic latitude in radians to
geocentric latitude in radians on a reference ellipsoid given a first eccentricity.
Accelerated Performance for geoshow, mapshow, and bufferm
Functions geoshow, mapshow, and bufferm run substantially faster in many cases,
especially when vector display is being controlled via symbol specs in mapshow and
geoshow.