|At a Glance|
|Name||Lingwood Trig Beacon|
|Location||GPS Co-ordinates: S 29° 46.067 E 030° 50.648|
Steel vanes on a concrete plinth.
Altitude 499.90 MSL
Trigonometric beacons which were used for land surveying throughout South Africa. These beacons have been replaced by the use of modern Global Positioning System (GPS) technology.
The error margin of the measurements based on the beacons varied depending on the quality of the instruments used but was in the region of 20m. The accuracy of the advanced GPS systems is now within a few millimeters.
The Lingwood Trig Beacon was most probably built in the 1950’s.
The position offers a 360° view of Kloof with views extending out to sea in Umhlanga on the north-east and towards the Drakensberg on the west.
It is the highest point on the eastern escarpment of Krantzkloof Nature Reserve.
The beacon is often erroneously referred to as “Gibson’s Beacon” as the Gibson family lived in nearby Windsor Road.
The beacon fell into disrepair and the metal vanes broke off after many years of neglect. Kloof Conservancy repaired and restored the beacon during 2013 to preserve this bit of local history.
The trigonometric beacons (trig beacons) in South Africa originated from the Western Cape, Cape Town to be exact and they were based on star observations and precisely measured baselines . Sir Thomas Maclear between 1833 and 1870 and Sir David Gill between 1879 and 1907 were initially tasked to verify the size and shape of the earth in the Southern Hemisphere and later to provide geodetic control for topographic maps and navigation charts. From these beginnings the network was extended to eventually cover the entire country and which eventually comprised about 29000 highly visible trigonometric beacons on mountains, high buildings and water towers.
The trig beacons were fixed mainly by angle observations for the horizontal position and trig heighting was used to determine the heights. The position of the trig beacon is at the centre of the pillar and the height is mainly at the top of the pillar. Their heights are based on Mean Sea Level (MSL).
Trig beacons are grouped together to form a network of triangulation and are grouped together according to their positions on earth with the reference to the degree squares e.g. those that are in degree square 2930 will be grouped together and those in degree square 3030 will be grouped together. The degree squares are defined by the lines of Latitude and Longitude.
Note: These notes are an extract from "TYPES OF SURVEY CONTROL" – ETHEKWINI MUNICIPALITY
M. Seedat, S. Thusi, M. Zaca, N. Ndaba & S. Ndlovu – Surveying & Land Information Dept