PURPOSE: This rule prescribes the acceptable accuracy of first and second order control.

1. (1) The accuracy of a horizontal control station is classified according to constrained and unconstrained, relative accuracy of the distance between stations, and the positional accuracy of the station relative to the stations held fixed in the adjustment. If the requirements for all three (3) criteria are not satisfied, the station shall fail to qualify for the classification.

2. (2) First Order Horizontal Control.

   1. (A) The relative accuracy of the distance between directly connected adjacent stations shall be equal to or less than twelve millimeters (12 mm) for distances equal or less than one kilometer (1 km), and ten parts per million (10 ppm) for distances greater than one kilometer (1 km).
   2. (B) The positional accuracy of a station shall be thirty millimeters (30 mm) in urban areas and sixty millimeters (60 mm) in rural areas.

3. (3) Second Order Horizontal Control.

   1. (A) The relative accuracy of the distance between directly connected adjacent stations shall be equal to or less than twenty-five millimeters (25 mm) for distances equal to or 2 CSR 90-62

less than one kilometer (1 km), and twenty parts per million (20 ppm) for distances greater than one kilometer (1 km).

1. (B) The positional accuracy of a station shall be sixty millimeters (60 mm) in urban areas and one hundred (100) mm in rural areas.

1. (4) To fully qualify as a first or second order control station, the station must be accepted and published by the Missouri Department of Agriculture or the National Geodetic Survey or its successor organization.

AUTHORITY: section 60.451.3., RSMo 2016.* Rule originally filed as 10 CSR 30- 4.030. Original rule filed May 3, 1994, effective Dec. 30, 1994. Moved to 2 CSR 90- 62.030 and amended: Filed Dec. 1, 2016, effective June 30, 2017.

*Original authority: 60.451.3, RSMo 1984, amended 2013.