This inventory includes over 6000 records of historic gardens and designed landscapes. The initial survey was carried out in two phases. Phase 1 commenced in 2003 with a search to identify sites. Phase 2, which commenced in 2005, was a desk-based initial assessment of condition and survival. Both phases were carried out by Richards, Moorehead & Laing Ltd. on behalf of the Department of Environment, Heritage and Local Government.
The objective of Phase 1 was to identify all the sites shown on the early Ordnance Survey map sheets. A comprehensive search was carried out using the 179 relevant 1st or 2nd Edition 1inch OS map sheets (there are 205 sheets in all, of which 26 cover the area of Northern Ireland.) These were published as the 1st, 2nd and Revised 2nd Edition between 1850 and 1895. Demesnes are shown using a grey tone on these early editions. Details for each site were recorded including:
- Name shown on the map and any alternative names found;
- Presence on the 1st, 2nd and Revised 2nd Edition 1inch OS maps and sheet number;
- OS sheet and grid reference on the modern OS Discovery 1:50,000 Series.
A library search was carried out to record important bibliographical references. Paper files were prepared for each site to which this bibliographic material was added. The bibliographical lists are also included in the gazetteer. Further general lists are included for each county and the country. The paper files are now housed in the library of the National Botanic Gardens, Glasnevin.
The objective of Phase 2 was to make an initial assessment of the condition and survival of all the sites identified using current OS aerial photography (2000) and OS 1st Edition 6 inch mapping (1833 and 1846).
A web-based Geographical Information System (GIS) was used to review digital map and aerial photo images. This enabled both map and photo to be presented at the same scale and orientation and overlaid to readily show differences and common features. The surveyors prepared a summary Site Survey Report for each site.
The digital aerial photos used had a resolution of about 1 pixel per 1m2. A pixel is a square dot of information that makes up a tiny part of the digital image. A pixel in the images used represents about 1m2 on the ground. If an object is smaller than 1m2 across it will not be visible.
The Site Survey Report is the surveyor's comment on what could be identified on the map and the aerial photo and what could be interpreted about the site's condition based on a comparison of the two.
The Site Survey Report includes:
- Initial Overview: general comment on the overall site and impact of any recent development;
- Architectural Features: the presence and survival of the principal buildings and other structures such as gate lodges and garden buildings;
- Movement within Site: the presence of drives, walks and avenues and changes in these since the maps were made;
- Landscape Features: the presence of key features such as walled gardens, woodland, orchards, formal gardens, vistas, lakes and rivers. A short comment will normally be provided on the character and condition of the landscape.
In the Initial Overview there is a reference to the Feature Richness Index. This is a figure that can range from 1 to 6 and represents the total number of major traditional garden features identified. It could be a high figure for a site that is partially destroyed, but could also be a low figure for a site that is virtually complete and unchanged. The Feature Richness Index is not an indication of heritage significance or merit. It should also be noted that features could survive that are not visible on the aerial photography.
There are five possible options identified for the Statement of Condition:
- Main features substantially present: - no loss of integrity
- Main features substantially present: - some loss of integrity
- Main features substantially present:- peripheral features unrecognisable
- Main features unrecognisable: - peripheral features visible
- Virtually no recognisable features
It must be stressed that the statement of condition is not an indication of a site's heritage importance and should not be used to justify statements about the site's importance or merit. A field survey will be required to confirm a site's survival and evaluate its heritage significance.
The objective of Phase 3 is to carry out a more detailed site inventory and assessment. A standard field recording form is used to record location, townland(s), details of mapping, bibliography, a Summary Description and Site Data including:
- Principal Building
- Entrances/Gate Lodges
- Access Routes
- Ornamental Grounds and Gardens
- Plants/Plant Collections
- Ornamental Garden Buildings
- Ornamental Garden Structures
- Productive Gardens
- Productive Garden Buildings
- Walled Gardens Comlex
- Historical/Cultural Associations
- Other Features
For each site there is also a Statement of Significance with seven possible options:
- Significant site, substantially intact - built structures and planting in good condition
- Significant site - some loss of integrity
- Site of historical importance - now partially derelict or destroyed
- Modest site - with buildings and planting surviving
- Modest site - now partially derelict or destroyed
- Site of historic interest only
- Site not inspected