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  • 投影知识点

    投影名称 英文名称 投影类型 投影性质

    高斯-克吕格投影(在英美国家称为横轴墨卡托投影)

    Gauss-Kruger 等角横切圆柱投影/等角横切椭圆柱投影 投影后中央经线保持长度不变,即比例系数为1
    通用横轴墨卡托投影 Universal Transverse Mercator,UTM 等角横轴圆柱投影 圆柱割地球于南纬80度、北纬84度两条等高圈,投影后两条割线上没有变形,中央经线上长度比0.9996。
    横轴墨卡托投影,又称为高斯-克吕格投影 Transverse Mercator,TM 等角横切圆柱投影  
    墨卡托投影 Mercator 等角正切圆柱投影  

    Web墨卡托投影

    http://hi.baidu.com/liongg/item/2840be728b738b10d0dcb39b

    Web MercatorSpherical Mercator 等角正切圆柱投影 它与常规墨卡托投影的主要区别就是把地球模拟为球体而非椭球体

    如下是从ArcGIS帮助文档中摘出来的:

    A sphere-based version of Mercator is used by several web mapping sites. The sphere's radius is equal to the WGS 1984 semimajor axis, 6378137.0 meters.

    Two methods exist for emulating the Mercator projection used by the web services.

    If the Mercator implementation supports spheroids (ellipsoids), the projected coordinate system must be based on a sphere-based geographic coordinate system. This will force the use of sphere equations. The implementation of Mercator auxiliary sphere has sphere equations only.

    In addition, it has a projection parameter that identifies what to use for the sphere radius if the geographic coordinate system is ellipsoidal based. The default value of zero (0) uses the semimajor axis.

    ArcGIS中实现了Mercator(WGS84)和Mercator(sphere)

    看看他们参数,1和2即为上面所述的两种方式,即像Google地图所使用的Web Mercator. 2和4几乎一致,只是2多了个属性:

    WGS_1984_Web_Mercator
    WKID: 3785 权限: EPSG
    
    Projection: Mercator
    False_Easting: 0.0
    False_Northing: 0.0
    Central_Meridian: 0.0
    Standard_Parallel_1: 0.0
    Linear Unit: Meter (1.0)
    
    Geographic Coordinate System: GCS_WGS_1984_Major_Auxiliary_Sphere
    Angular Unit: Degree (0.0174532925199433)
    Prime Meridian: Greenwich (0.0)
    Datum: D_WGS_1984_Major_Auxiliary_Sphere
      Spheroid: WGS_1984_Major_Auxiliary_Sphere
        Semimajor Axis: 6378137.0
        Semiminor Axis: 6378137.0
        Inverse Flattening: 0.0
    WGS_1984_Web_Mercator
    WGS_1984_Web_Mercator_Auxiliary_Sphere
    WKID: 3857 权限: EPSG
    
    Projection: Mercator_Auxiliary_Sphere
    False_Easting: 0.0
    False_Northing: 0.0
    Central_Meridian: 0.0
    Standard_Parallel_1: 0.0
    Auxiliary_Sphere_Type: 0.0
    Linear Unit: Meter (1.0)
    
    Geographic Coordinate System: GCS_WGS_1984
    Angular Unit: Degree (0.0174532925199433)
    Prime Meridian: Greenwich (0.0)
    Datum: D_WGS_1984
      Spheroid: WGS_1984
        Semimajor Axis: 6378137.0
        Semiminor Axis: 6356752.314245179
        Inverse Flattening: 298.257223563
    WGS_1984_Web_Mercator_Auxiliary_Sphere
    Sphere_Mercator
    WKID: 53004 权限: ESRI
    
    Projection: Mercator
    False_Easting: 0.0
    False_Northing: 0.0
    Central_Meridian: 0.0
    Standard_Parallel_1: 0.0
    Linear Unit: Meter (1.0)
    
    Geographic Coordinate System: GCS_Sphere
    Angular Unit: Degree (0.0174532925199433)
    Prime Meridian: Greenwich (0.0)
    Datum: D_Sphere
      Spheroid: Sphere
        Semimajor Axis: 6371000.0
        Semiminor Axis: 6371000.0
        Inverse Flattening: 0.0
    Sphere_Mercator
    WGS_1984_World_Mercator
    WKID: 3395 权限: EPSG
    
    Projection: Mercator
    False_Easting: 0.0
    False_Northing: 0.0
    Central_Meridian: 0.0
    Standard_Parallel_1: 0.0
    Linear Unit: Meter (1.0)
    
    Geographic Coordinate System: GCS_WGS_1984
    Angular Unit: Degree (0.0174532925199433)
    Prime Meridian: Greenwich (0.0)
    Datum: D_WGS_1984
      Spheroid: WGS_1984
        Semimajor Axis: 6378137.0
        Semiminor Axis: 6356752.314245179
        Inverse Flattening: 298.257223563
    WGS_1984_World_Mercator
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  • 原文地址:https://www.cnblogs.com/yhlx125/p/3417677.html
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