|
|
A Surveyor's Norman Conquest (Tech Trends Feature)
2 Feb, 2009 By: Kenneth WongHigh-definition scanning helps document historic Nenagh Castle.
In 1860, Bishop Michael Flannery launched a plan to upgrade Nenagh Castle, a fine specimen of Norman architecture located on the patch of land he'd just purchased in Tipperary, Northern Ireland. For funding, he relied on donors from North America, among other sources. Naturally, when the U.S. Civil War broke out in 1861, the flow of funds dried up, and the bishop was forced to halt construction. Flannery did manage to leave his mark on the castle in the form of a series of battlements with windows. Little did the bishop know his crowning legacy would help solve a surveyor's dilemma one-and-a-half centuries later.
HDS Comes to Northern Ireland
Theobald Fitzwalter, a hereditary baron and the steward of the region at the time, decided to make Nenagh his seat of power in 1200. During his reign, he started to build Nenagh Castle as his residence, but it wasn't completed until his son's time.
 In this article |
The castle now is one of the major tourist attractions in County Tipperary. If the baron's builders used any construction drawings, they haven't been unearthed. The Norman carpenters certainly didn't leave behind DWG files to chronicle their progress. So, in 2008, when the Office of Public Works (OPW) decided to undertake restoration works, they commissioned Gridpoint Solutions, a Belfast-based survey firm equipped with high-definition surveying (HDS) technology, to scan the site and help produce as-built drawings of the castle.
A few years ago, Gridpoint Solutions invested roughly $125,000 to acquire a Leica Geosystems HDS3000 laser scanner. HDS laser scanners remotely capture the detailed shape and geometry of target objects — usually existing architecture, facilities, or landscapes — in significantly reduced time. The HDS3000, for example, is reportedly capable of 6-mm accuracy for each scan point at a 50-m distance from the scanner. Leica's HDS hardware is complemented by the company's Cyclone and CloudWorx series of software modules and plug-ins that let surveyors and CAD professionals process the rich point-cloud data from the scanners and convert them into CAD-compatible formats (figure 1).
 Figure 1. In Ireland, a market for HDS has emerged from the need to digitally archive heritage sites such as Nenagh Castle (top photo). HDS devices allow surveyors to remotely capture the shape of the target object in point clouds (middle and bottom images). |
"We were, in fact, the first survey firm to offer HDS services in Northern Ireland," said Conor Graham, director of Gridpoint Solutions. "We've found a good market for it in the heritage preservation projects."
In recent years, North and South Ireland administrations have adopted digital preservation and archiving as the solution to document archeological sites destined to be replaced by new construction. On its web site, the Public Record Office of Northern Ireland (PRONI) declares its "statutory responsibility for selecting, acquiring, preserving, and maintaining access to records that form part of Northern Ireland's unique cultural heritage." The task traditionally was done on paper, but PRONI points out, "Northern Ireland Civil Service and wider public-sector business needs have changed and, in order to support that change, PRONI has to be in a position to provide a digital archiving service."
1 2 3
|
|
AutoCAD Tips!
Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's Tips & Tricks Tuesdays free e-newsletter and we'll notify you every time a new video tip is available. All exclusively from Cadalyst! |
|
