Difference between Gaussian-kruger projection and UTM projection

Source: Internet
Author: User

Gaussian-kruger projection and UTM projection are both variants of the horizontal mocator projection, at present, some foreign software or the supporting software of imported foreign instruments often do not support Gaussian-gram projection, but support UTM projection. Therefore, UTM projection is often used as Gaussian-gram projection. From the perspective of projection ry, Gaussian-gram projection is an equivalent cross-section cylindrical projection. After projection, the central longitude line remains unchanged, that is, the proportional coefficient is 1; UTM projection is an equal-angular horizontal axis cut cylindrical projection. The cylindrical cut Earth is located at 80 degrees south latitude and 84 degrees north latitude, and there is no deformation on the two cut lines after the projection, the central longitude line length ratio is 0.9996.

UTM Projection Method and Gaussian - Similar to Keru projection 84 Degrees to latitude 80 Degrees are divided by longitude 60 Tape , Each tape 6 Degrees . From the west longitude 180 Degrees start , The two standard weft cables are from the central longitude line 180 km Left and right , The ratio of the central longitude is 0.9996.

According to the calculation results, the main difference between the two lies in the proportional factor. The proportional coefficient of the center longitude line of Gaussian-gram projection is 1, and the UTM projection is 0.9996, X [UTM] = 0.9996 * X [Gaussian] and y [UTM] = 0.9996 * Y [Gaussian] can be used for coordinate transformation between Gaussian-gram projection and UTM projection (note: for example, if the vertical axis of the coordinate is 500000 meters west, the Y value must be subtracted from the 500000 multiplied proportional factor plus 500000) during conversion ).

from the perspective of the split-band method, the start point of the split-band is different between the two. Gaussian-gram projects are projected from the 0-degree meridian at intervals of 6 degrees from west to east, the central longitude of the 1st band is 3 °; the UTM projection is from the west longitude 180 °, and the longitude of the 1st band is-177 °, therefore, the 1st band of Gaussian-gram projection is the 31st band of UTM. In addition, the East pseudo offset of the two projections is 500 kilometers, the North pseudo offset of Gaussian-gram projection is zero, the northern pseudo offset of UTM projection is zero, and that of the southern hemisphere is 10000 kilometers.
Gaussian-kerlvge projection and UTM projection Coordinate System
Gaussian-kerlvge projection and UTM projection are independently projected by means of the binning method, so each coordinate is an independent system. Take the central longitude line (L0) Projection as the vertical axis X, the equator projection as the horizontal axis Y, and the intersection of the two axes is the coordinate origin of each belt. In order to avoid negative horizontal coordinates, the Gaussian-gram projection and UTM Northern Hemisphere projection require that the vertical axis be shifted 500 kilometers west as the starting axis, while the UTM Southern Hemisphere projection not only shifts the vertical axis 500 kilometers west, the horizontal axis is 10000 kilometers south. Since the coordinates of each projection belt of Gaussian-gram projection and UTM projection are relative values of the local coordinate point, the coordinates of each belt are exactly the same. In order to distinguish which region a coordinate system belongs, generally, a belt number is added before the x-axis coordinates, such as (4231898 M, 21655933 M). Among them, 21 is the belt number.

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