PURPOSE: This rule describes the classes of horizontal control. (1) First Order Horizontal Control Classification. The purpose of this class of survey is to establish primary horizontal control for the Missouri Geographic Reference System or the National Spatial Reference System.

1. (2) Second Order Horizontal Control Classification. The purpose of this class of survey is to establish secondary and supplemental horizontal control stations of the Missouri Geographic Reference System or the National Spatial Reference System.
2. (3) Both first and second order stations are dependent stations constrained to the existing first and second order stations of the Missouri Geographic Reference System and/or the National Spatial Reference System. These stations are intended to be used to meet the needs of mapping, geographic information systems, land information systems, property boundary surveys, and design surveys.

AUTHORITY: sections 327.041 and 327.272, RSMo 2016.* This rule originally filed as 4 CSR 30-18.020. Original rule filed May 3, 1994, effective Dec. 30, 1994. Moved to 20 CSR 2030-18.020, effective Aug. 28, 2006. Non-substantive change filed Oct. 21, 2015, published Dec. 31, 2015. Amended: Filed Nov. 18, 2016, effective June 30, 2017. *Original authority: 327.041, RSMo 1969, amended 1981, 1986, 1989, 1993, 1995, 1999, 2001, 2010, 2014 and 327.272, RSMo 1969, amended 1981, 1999, 2010, 2014, 2016.