Mound of the Hostages
The Mound of the Hostages takes its name from the medieval Irish designation of the monument Duma na nGiall, a name associating the monument with the symbolic exchange of hostages which must have taken place at Tara in the medieval period. It is, however, a passage tomb built around 3000 BC and part of the Boyne Valley culture. The passage is 4m long and was divided by sill-stones into three compartments, the floor of each formed by a large, flat slab. It is orientated roughly east – west with the entrance, which is flanked by two portal stones, facing east. One of the side-stones is decorated with concentric circles and zigzag patterns characteristic of passage tomb art. Although disturbed during the insertion of further burials during the Early Bronze Age, the assemblage of primary, Late Neolithic cremated burials and accompanying grave goods is one of the finest in the country.
This was a collective burial chamber probably receiving the cremated remains of the dead over many years. A layer of undisturbed primary burial deposits, 30cms deep, for instance, was found in the central compartment and was accompanied by the full range of artefacts normally associated with these tombs – including the distinctive passage tomb pottery (Carrowkeel Ware), bone pins, pendants and stone balls.
Some forty burials dating to the Early/Middle Bronze Age were found in the clay mantle covering the cairn of the passage tomb. These single burials signify a shift away from the collective burials of the earlier period and reflect the emergence of a more hierarchical social structure based on individual wealth. Although a number of inhumation burials of this period were placed in the passage, only one was found in the mantle of clay: all of the remaining burials were cremated. Many of these were contained under inverted cinerary urns which were in some cases accompanied by smaller food vessels and miniature pots. Some of the burials were contained in stone-built cists and in some cases two or more burials were placed in the same pit. The sole inhumation burial in the mound was that of an adolescent, about 14—15 years of age. Around the area of the neck were the remains of a necklace of jet, amber, bronze and faience beads and near the feet lay a small bronze knife and the very corroded remains of what may have been a bronze awl. That this individual was of privileged rank in society can be deduced from the exceptional grave goods, in particular the faience beads which may originate from the eastern Mediterranean and were a rare and exotic item in Bronze Age Ireland.
Ráith na Rí in medieval descriptions is said to have enclosed three wonders, the Forradh, Teach Cormaic and Múr Tea. The Irish word forradh is likely to mean ‘a mound or platform’. It is possible that the monument functioned as the location for inaugurations of kings of Tara.
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.