importance of accuracy in land survey

Accuracy is one of the most important factors of land surveys. The purpose of a land survey is to accurately map and designate land boundaries. Any
inaccuracies can lead to potential legal issues down the track. Some types of land surveys require even more accuracy than others as they are used to help
establish where to construct buildings by taking into account topographic and hydrological features such as sewage systems and trees. Any inaccuracies could
cause difficulties in the building process.
The accuracy of land surveys is particularly important when they are used for map making as the wider community relies on the accuracy of maps and assumes
that they are precise documents. Note the 2005 version of ALTA specifications, "ALTA" stands for American Land Title Association, states a Positional Accuracy
of 0.07 feet or 20mm in new money, plus 50 parts per million. Many of the modern instruments used by a Land Surveyor have an accuracy of distance
measurements to within 2mm +/- 2 ppm but that alone does not assure compliance with the ALTA standards. The ALTA Standards require that these condition
are taken into account: The Relative Positional Accuracy may be tested by either:
1. Comparing the relative location of points in a survey as measured by an independent survey of higher accuracy or; In other words the survey would required
to be a traverse ending at its point of origin, beginning and ending on two different points of higher order. These higher orders can be monuments can be NGS
monuments, or monuments established on an older survey where the location was determined in accordance with condition 2 as here.
2. the results of a minimally constrained correctly weighted least square adjustment of the survey.
The surveyor needs to apply a squares adjustment program. Therefore the surveyor needs to know the accuracy standards of their equipment and surveying
techniques. This means they must know the distance and angular measurement specifications of their instrument and an estimate of such things as centering
tolerance.