Under its Open Data Strategy Defra and its agencies are increasing the range of the data that they provide. As part of this strategy, LiDAR data is available for England free of charge, as a series of geo-referenced tiles. For archaeological purposes, DTM (digital terrain model) is generally most useful, as it removes buildings and vegetation.You will need suitable software to process the data, examples of which are given below.
Without question the world’s leading Open source GIS software package - and it’s free! It can even be used to process point cloud data such as LiDAR, but many people prefer to process elsewhere then import the results
IMPORTANT NOTE: At the time of writing (Jan. 2017)the Scottish Government has no plans to make their LiDAR data available to the public.
Various series of OS and Bartholomew maps are available, although most important for our purposes are the 6 inch to the mile Ordnance Survey maps, not just of Scotland, but also of England and Wales. Digitisation of the entire 25inch to the mile map series is in progress. There are two viewing options for the 6 inch, either as a seamless zoomable layer, or as individual sheets
The Ordnance Survey’s online version of its well known paper maps. This is unfortunately now a subscription only service. If you would like to use OS maps online for free, the best alternative is Bing, from Microsoft (see below).
Ordnance Survey offer a range of quality assured, regularly updated products that enable you to analyse your data, build interactive websites and create stunning visuals – and they're all free. Products like OS Terrain 50, a 50m digital gridded terrain model are excellent for creating 3D terrain maps in another product such as QGIS
Everyone is familiar with Google Maps, however hardly anyone seems to be aware that Microsoft’s alternative has OS mapping (to 1:25000) in the UK for free! In the drop-down box in the top right corner, Ordnance Survey is the fifth one down and easy to miss.
A highly unlikely source of processed LiDAR (DSM) data for England and Wales. The Environment Agency data has been used, so coverage is only about 50%, and of course there’s a hole where Scotland should be. The interface is easy to use, and it’s actually a very good starting point before going to the trouble of processing data yourself.
This very useful free software, developed by the Institute of Anthropological and Spatial Studies (IAPŠ) at the Research Centre of the Slovenian Academy of Sciences and Arts (ZRC SAZU), allows the creation of a mosaic from multiple data tiles, which can then be processed in a variety of ways. The software does not have a viewer, so you can’t see the results as you go, but with the right hardware it is capable of working with very large chunks of data.
The National Collection of Aerial Photography, based in Edinburgh, holds over 26 million aerial photos of places across the world. They are all viewable online, and coverage of Britain is reasonably good
The Cambridge University Collection of Aerial Photography (CUCAP) is the result of airborne survey campaigns which were started in 1947 by the pioneering JK St Joseph. Since then the collection has grown to almost 500,000 images of obliques and verticals in black and white, colour and infra-red. Virtually the whole of Britain has been covered, with the obliques depicting a wide variety of landscapes and features and the verticals being of survey quality, can be used in mapping projects. Not all images are yet available online, but an increasingly valuable resource.
The MAGIC website provides authoritative geographic information about the natural environment from across government. The information covers rural, urban, coastal and marine environments across Great Britain. It is presented in an interactive map which can be explored using various mapping tools that are included. Natural England manages the service.