Sinusoidal image projections aim to maintain equal areas throughout all grid sections. Here we also note that an alternative form of this projection (the transverse mercator) may be used for very tall vertical panoramas. This projection is perhaps the most recognizable from its use in flat maps of the earth.

Mercator image projections are most closely related to the cylindrical and equirectangular projection types mercator represents a compromise between these two types, providing for less vertical stretching and a greater usable vertical angle of view than cylindrical, but with more line curvature. A camera with a fisheye lens is extremely useful when creating panoramas that encompass the entire sphere of vision, since these often require stitching just a few input photographs. This would be characterized by (otherwise straight) lines becoming progressively more curved the farther they get from the center of the image grid. Fisheye projections are also limited to vertical and horizontal angles of view of 180 degrees or less, yielding an image which fits within a circle. These are generally not used as an output format for panoramic photography, but may instead represent the input images when the camera lens type being used for photo stitching is a fisheye lens. It is for this reason that rectilinear projections are generally not recommended for angles of view much greater than 120 degrees.ДЇisheye image projections aim to create a flattened grid where the distance from the center of this grid is roughly proportional to actual viewing angle, yielding an image which would look similar to the reflection off of a metallic sphere. Its primary disadvantage is that it can greatly exaggerate perspective as the angle of view increases, leading to objects appearing skewed at the edges of the frame. This projection type is what most ordinary wide angle lenses aim to produce, so this is perhaps the projection with which we are most familiar. Rectilinear image projections have the primary advantage that they map all straight lines in three-dimensional space to straight lines on the flattened two-dimensional grid. Cylindrical projections maintain more accurate relative sizes of objects than rectilinear projections, however this is done at the expense of rendering lines parallel to the viewer's line of sight as being curved (even though these would otherwise appear straight).

Cylindrical projections are also the standard type rendered by traditional panoramic film cameras with a swing lens. It is for this reason that cylindrical projections are also not suitable for images with a very large vertical angle of view. Equirectangular projections can show the entire vertical and horizontal angle of view up to 360 degrees.Д¬ylindrical image projections are similar to equirectangular, except it also vertically stretches objects as they get closer to the north and south poles, with infinite vertical stretching occurring at the poles (therefore no horizontal line is shown at the top and bottom of this flattened grid). Horizontal stretching therefore increases farther from the poles, with the north and south poles being stretched across the entire upper and lower edges of the flattened grid. If all the above image projection types seem a bit daunting, try to first just read and understand the distinction between rectilinear and cylindrical (shown in bold), as these are the ones which are most widely used when photo stitching digital panoramas.Д®quirectangular image projections map the latitude and longitude coordinates of a spherical globe directly onto horizontal and vertical coordinates of a grid, where this grid is roughly twice as wide as it is tall. Projection Type for Flattened Sphere: Equirectangular (100% Coverage)

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