What is the difference in elevation when switching between WGS 84 and NAD 27?
Maps using the NAD 27 datum also generally use the National Geodetic Vertical Datum of 1929. Elevations are measured against Mean Sea Level (MSL). The two datums (horizontal and vertical) are, essentially independent of one another. Maps using the more recent NAD 83 datum (very similar to WGS 84.. within a meter or two) will still have essentially the same elevations above MSL. It is interesting how the GPS (based on WGS 84) works. Four or more satellites can be used to determine three position dimensions and time. Position dimensions are computed by the receiver in Earth-Centered, Earth-Fixed X, Y, Z (ECEF XYZ) coordinates. When more than “the best four” satellites are used, this is called an over-determined solution. Most receivers compute (and store) the geodetic (in WGS 84) coordinates of latitude, longitude and height above the ellipsoid (HAE). WGS 84 coordinates are transformed and displayed in whatever datum you choose. Always choose the datum of the map you are working with. Th
Maps using the NAD 27 datum also generally use the National Geodetic Vertical Datum of 1929. Elevations are measured against Mean Sea Level (MSL). The two datums (horizontal and vertical) are, essentially independent of one another. Maps using the more recent NAD 83 datum (very similar to WGS 84.. within a meter or two) will still have essentially the same elevations above MSL. It is interesting how the GPS (based on WGS 84) works. Four or more satellites can be used to determine three position dimensions and time. Position dimensions are computed by the receiver in Earth-Centered, Earth-Fixed X, Y, Z (ECEF XYZ) coordinates. When more than “the best four” satellites are used, this is called an over-determined solution. Most receivers compute (and store) the geodetic (in WGS 84) coordinates of latitude, longitude and height above the ellipsoid (HAE). WGS 84 coordinates are transformed and displayed in whatever datum you choose. Always choose the datum of the map you are working with. Th
