地图投影的选择、设计和变换(国外英文资料).doc

地图投影的选择、设计和变换(国外英文资料) The purpose and nature of a map This is the most important factor. Once identified, the properties of the projection can be determined. Equivalent projection: applicable to economic, political and natural maps Equal Angle projection: applicable to navigation, military and topographic maps Equidistant projection: maps that are equally important for all forms of deformation, such as ordinary maps Arbitrary projections: instructional maps and a variety of scientific views. Special maps have special requirements for projection, such as spherical projection, equal distance bearing projection, time zone diagram, and so on. The shape and geographic location of the drawing area You can determine the type of the projection Circular area: bearing projection Middle latitude extension: conic projection An area near the equator or along the sides of the equator: the cylindrical projection of the positive axis North and south extension: transverse cylindrical projection or polyconic projection Oblique cylindrical or conical projection In the small area, the influence of various projections is not very large, at this time, the calculation is convenient, the grid simple projection. The size of the drawing area The influence of the performance is more complicated due to the increase of area, and more factors are to be considered. Large scale maps do not require more consideration of the shape and location of the region. In practice, the area of no more than five to six hundred square kilometers of the area, the selection of the projection is 0.5%. In the area of 3.5 to 4.0 kilometers, the length of the area is 2 to 3 percent. In larger areas, they tend to be more than 3% in length. For medium or small areas, the projection option is generally considered only geometrically, regardless of the purpose and nature of the map. ? The projection of the world map World map projection of the main consideration to ensure the overall global deformation is not large, accor