Below shows the various surfaces and orientation of the surfaces with respect to the ellipsoid axes. The three surfaces for projecting the ellipsoid are a cylinder, a cone and a plane. The main projection types used in E&P are Transverse Mercator and Lambert Conformal Conic.
Other projection types that occur less frequently are: Mercator, Oblique Mercator (Alaska) Oblique Stereographic (Syria), Albers Equal Area. The majority of the standard projections in use in E&P are listed with parameters in the EPSG database.
There are many ‘standard’ projection parameter definitions, but a project projection can be custom designed for specific purposes if needed. In general, one or two of the following criteria can be preserved when designing a projection:
Shape
Area
Scale
Azimuth
The majority of the projections we use are conformal. This means that scale at a point is the same in all directions, angular relationships are preserved (but not necessarily north reference) and small shapes and areas are preserved.
They are also generally computational.
Below shows that making the plane surface secant to the ellipsoid allows for a greater area to be covered with an equivalent scale distortion.
Feedback
Post your comment on this topic.