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A (general) conical surface is the unbounded surface formed by the union of all the straight lines that pass through a fixed point — the apex or vertex — and any point of some fixed space curve — the directrix — that does not contain the apex. Each of those lines is called a generatrix of the surface.
In Metropolitan France, the official projection is Lambert-93, [6] a Lambert conic projection using RGF93 geodetic system [7] and defined by references parallels that are 44°N and 49°N. The National Spatial Framework for India uses Datum WGS84 with a LCC projection and is a recommended NNRMS standard.
Coordinate surfaces of the conical coordinates. The constants b and c were chosen as 1 and 2, respectively. The red sphere represents r = 2, the blue elliptic cone aligned with the vertical z-axis represents μ=cosh(1) and the yellow elliptic cone aligned with the (green) x-axis corresponds to ν 2 = 2/3.
Snyder [6] describes generating formulae for the projection, as well as the projection's characteristics. Coordinates from a spherical datum can be transformed into Albers equal-area conic projection coordinates with the following formulas, where is the radius, is the longitude, the reference longitude, the latitude, the reference latitude and and the standard parallels:
The reference point (λ 0, φ 0) with longitude λ 0 and latitude φ 0, transforms to the x,y origin at (0,0) in the rectangular coordinate system. [5] The Y axis maps the central meridian λ 0, with y increasing northwards, which is orthogonal to the X axis mapping the central parallel φ 0, with x increasing eastwards. [5]
A surface that can be unfolded or unrolled into a plane or sheet without stretching, tearing or shrinking is called a developable surface. The cylinder, cone and the plane are all developable surfaces. The sphere and ellipsoid do not have developable surfaces, so any projection of them onto a plane will have to distort the image.
In mathematics, a spherical conic or sphero-conic is a curve on the sphere, the intersection of the sphere with a concentric elliptic cone. It is the spherical analog of a conic section ( ellipse , parabola , or hyperbola ) in the plane, and as in the planar case, a spherical conic can be defined as the locus of points the sum or difference of ...
Wallis's conical edge is also a kind of right conoid. It is named after the English mathematician John Wallis, who was one of the first to use Cartesian methods to study conic sections. [1] Figure 2. Wallis's Conical Edge with a = 1.01, b = c = 1 Figure 1. Wallis's Conical Edge with a = b = c = 1