The video below demonstrates the importance of light for identifying potential archaeological features. Flat light or overcast conditions, which limit shadows, make it extremely difficult to differentiate the small topographical changes that may be indicative of archaeological features.
In the video below a drone / UAV survey was undertaken to create a detailed 3D model or Digital Surface Model (DSM). The DSM, as a software construct of the 3D surface of the ground, can have its texture changed and can be lit from any angle providing the shadows that may otherwise be lacking.
Impact GIS undertook a drone survey of Killirsa Graveyard in County Galway to generate high resolution orthophotography for mapping of grave plots. Grave plots were mapped using Geographic Information System (GIS) software, allowing for data associated with each grave plot to be stored in an accompanying database. See the slide show below.
Bing aerial imagery of Killursa
Online sources of aerial photography are not of a sifficiently high resolution to be able to map grave plots
Drone survey of Killursa
High resolution orthophotography generated from a drone survey
Extract of drone survey
An extract from the drone survey showing the resolution of the orthophotography
Grave plots and other features mapped
Grave plots and other features mapped using Geographic information system software
Map of plots with reference grid
A 10m x 10m grid with alphanumeric labels overlaid to aid in locating individual grave plots
Killursa map with index of names
Index of names referenced to 10m x10m alphanumeric grid
Why use GIS?
Firstly it is probably best to explain what a Geographic Information System is. It’s all in the name, it is as system that allows you store information which is associated with location (geographic data). Most relevant to this project, GIS allows you to draw polygons, such as the squares and rectangles of the grave plots, and each one of these, as well as being spatially correct (in the right location), can have information about it stored in a database. So each grave plot can have the names, dates, inscriptions etc. stored and this information can be sorted, searched, filtered etc. This can form the basis of labelled paper maps, a searchable database, interactive online maps etc.