Measurement, Location, and Reestablishment of Lines, Angles, Elevations, and Features
Measurement, location, and reestablishment
This domain tests the field and computational evidence used to locate and reestablish lines, angles, elevations, and natural or manmade features. Florida expects the surveyor to state the basis of bearings, datum, and accuracy, and to distinguish ground distances from grid distances. The accuracy statement should match the survey purpose; a boundary survey is not automatically a topographic survey.
Core rules
- Bearings and azimuths are direction references; Florida practice typically uses bearings with a note stating the basis: true north, assumed north, or the Florida Coordinate System. Magnetic bearings change with declination and are not a boundary control unless the original survey used them.
- The Florida Coordinate System in Chapter 177, F.S., provides state plane coordinates based on NAD83; grid distances differ from ground distances by scale and elevation factors.
- Elevations must state the datum: NAVD 88 is the current vertical datum; GPS-derived ellipsoid heights require a geoid model to convert to orthometric heights.
- Reestablishment uses original evidence first, then proportionate measurement. For a lost corner on a straight line between two found corners, single proportion distributes the record distance by the measured distance.
Worked example
Two original corners are found 500.00 ft apart on the record line, but the measured distance is 502.00 ft. A lost corner was originally 200.00 ft from the west corner. Single proportion: 200.00 divided by 500.00, multiplied by 502.00, equals 200.80 ft from the west corner. The surveyor sets the reestablished corner at 200.80 ft, not 200.00 ft, because the found corners define the line's actual length. The surveyor records the method and ties.
Traps
Do not mix state plane grid distances with ground distances without applying scale and elevation factors. Do not use a magnetic bearing as the controlling direction when the original deed used true bearings. Do not report GPS ellipsoid heights as NAVD 88 elevations. Do not proportion a lost corner when original monument evidence survives nearby; proportion is a last resort, not a shortcut.