Page 119 - Manual for Activities directed at the Underwater Cultural Heritage

chaeological material, the site and the people who are connected to the site.
The following area search and survey methods are available for locating, exploring and recording a site:
1) the accumulated knowledge of local people, especially scuba divers and fishers; survey and excavation work should be taken as an opportunity to involve them in the conservation effort;
2) information in archives and libraries;
3) toponymy, palaeotopography and ethnography;
4) data from archaeology on land;
5) historical cartography and aerial photography;
6) topography and climatology;
7) findings of visual prospecting;
8) findings of marine geophysical prospecting;
9) findings of position fixing methods;
10) 2-dimensional and 3-dimensional survey me-
thods
Survey tools are used to sketch the site, to record the position of features (detail points on artefacts and structure in relation to known fixed control points), thus determining distances and bearings. Control points should be permanent, stable, uniquely identified, located around the exterior of the site and at different heights. At least four measurements should be taken from such control points to each detail point, always recording the depth.
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 © Archivo del Centre d’Arqueologia Subaquàtica de Catalunya. Planimetric survey on the wreck of the Triunfante sunk in 1795 in Sant Pere Pescador, Girona, Spain.
The planimetric survey gives a readily understandable impression of the extent and nature of a
site at a given time.The scale and techniques of planimetric surveys are determined by the map’s purpose and the assigned area. The traditional planimetric survey based on angular and linear measurements (diver survey applying triangulation) limits
itself to the plane features,
giving the site’s outlines and the locations of local objects without reproducing the relief of the area. In such surveying the outlines
of each feature and its contents are depicted.The topography is shown by a dumpy level.
This traditional approach and instruments have largely been replaced by the total station EDMs.The features which appear on the survey are fixed using x, y and z coordinates (eastings, northings and height).
The aim is to place the site and its features in relation to known points; the survey is tied in to OD heights and ordnance survey features to provide a contextual framework.
The survey is a necessary prerequisite to understanding and interpreting the archaeology, environment and subsequent factors affecting site formation.
Objective, methodology and techniques