The North American Datum of 1927 (NAD27) is one of the main three geodetic datums in North America. Meade’s Ranch NAD27 uses all horizontal geodetic surveys collected at this time using a least-square adjustment.

In surveying, cartography, and land-use planning, two North American Datums are in use for making lateral or "horizontal" measurements: the North American Datum of 1927 (NAD 27) and the North American Datum of 1983 (NAD 83). Both are geodetic reference systems based on slightly different assumptions and measurements.

2018年7月12日 · The NAD 27 was based on the Clarke Ellipsoid of 1866 and the NAD 83 is based on the Geodetic Reference System of 1980. The NAD 27 was computed with station …

2018年7月12日 · What are NAD 27 and NAD 83? The North American Datum of 1927 (NAD 27) is "The horizontal control datum for the United States that (was) defined by (a) location and azimuth on the Clarke spheroid of 1866, with origin at (the survey station) Meades Ranch." ... The geoidal height at Meades Ranch (was) assumed to be zero.

A horizontal datum (like NAD27) is a model that translates an ellipsoid into latitude and longitude coordinates. NAD27 put a fixed latitude and longitude position at Meade’s Ranch, Kansas (39° 13’26.686″ north latitude, 98° 32’30.506″ west longitude).

2011年7月28日 · There are two kinds of datum used in North America, namely, the North American Datum of 1927 (NAD 27) and the North American Datum of 1983 (NAD 83). Although the NAD 27 and NAD 83 are both geodetic systems, each one of them is …

As the name implies, datum transformations transform your data from one datum to another. The latitude and longitude location in the NAD27 datum differs from NAD83 or WGS84. This difference is known as a datum shift. Depending on where you are in North America, NAD27 and NAD83 may differ in tens of meters for horizontal accuracy.

It is the reference ellipsoid of the datum known as the North American Datum of 1927 (NAD27), but it is not the datum itself. For the Clarke 1866 spheroid to become NAD27, the ellipsoid of reference had to be attached at a point and specifically oriented to the actual surface of the earth.

2024年6月26日 · The primary difference between WGS84 and NAD27 is the level of accuracy. While WGS84 provides more precise coordinates, the difference between the two datums can be as much as 200 meters. Incorrectly using NAD27 instead of WGS84 can introduce significant errors in location measurements. Is NAD 27 geocentric?

Most USGS topographic maps published through 2006 use NAD27. US Topos (published after 2008) are georeferenced to NAD83 or WGS84. If you're using a topographic map and a GPS device, be sure that your device is set to the map's datum.