The shape of the monuments known as the Cláenfhearta, the ‘Sloping Trenches’, gave rise to a number of early tales. They were regarded as the remnants of the royal residence which collapsed when the king of Tara, Lugaid mac Con gave a false judgement. A second explanation for the shape of the monument is that it was the burial place of thirty princesses from Leinster slain by the king of Tara in revenge for the actions of the king of Leinster. These two monuments are ring-barrows that have been built on the edge of the steeply sloping western flank of the hill. In spite of the difficulty of digging a bank and ditch on so steep a gradient, both form complete circles and this supports the view that it was important to complete the circuit to comply with ritual convention. At over 80m in diameter, the northern site is by far the largest barrow at Tara. A hole was dug into the central mound, possibly by treasure hunters. The keen observer can make out the remains of a smaller barrow incorporated into the bank at the north side of the site.
The southern site of the Cláenfhearta is about 48m in diameter. There is a small mound on top of the main mound. There are three further mounds tucked in between the northern and southern Cláenfhearta and these too are probably burial monuments. South of this and along the crest of the ridge the remains of up to eight small, low barrows without banks can be identified.
FLI-MAP 400; an aerial LiDAR survey system, was initially designed to survey infrastructural assets such as roads, railways and electricity supply networks. The sensor system mounted beneath the main helicopter fuselage consists of:
- FLI-MAP 400; an aerial LiDAR survey system, was initially designed to survey infrastructural assets such as roads, railways and electricity supply networks. The sensor system mounted beneath the main helicopter fuselage consists of:
- Three 150 kHz LiDAR sensors (7◦ forward, nadir and 7◦ aft);
- Scanning angle 60◦
- Accuracy (relative) Horizontal 5 cm, Vertical 3 cm
- Multiple returns 4
- Two RTK GPS receivers – provide accurate location in used in conjunction with RTK base stations;
- Inertial Navigation System (INS)- continuously track the position, orientation, and velocity of the helicopter;
- Digital imaging (11 megapixel) and digital video capture
Resulting data sets include first return (DSM) and last return point (DTM, bare earth) models
Post-processing was completed in Geomagic Studio 2012 software: individual scans are edited, aligned, before a final surface is generated using global registration, fusion, and a small objects filter algorithm.. For dissemination purposes a 3D version of the model was generated using simplification, retopologisation and texturing processes utilising Autodesk Mudbox and 3DS Max.