Atlases of Wall features
There have been some notable maps produced of the Wall, starting with Horsley, but arguably reaching a peak under the auspices of the Ordnance Survey, with their 2nd edition of the Hadrian's Wall Two-Inch Map in 1972. This incorporated overlaid detail of the line of the curtain wall, ditch, Vallum, and military way, as well as the turrets, milecastles, and forts, distinguishing through colour both the visible (black) and the hidden (red) parts of the monument, as well as indicating where a degree of supposition was involved by means of broken lines.
The present atlas is being made available as a Google Earth KMZ file, an embedded Google Map, and Microsoft Virtual Earth links. The three technologies differ considerably: whilst Google Earth holds the data as an XML file on your computer, Microsoft's Virtual Earth stores it on a remote server and, crucially, has a limit of 200 items in any one Collection, requiring several Collections to cover all the features of the Wall. Until this is remedied, this severely limits the usefulness of the Microsoft version for the purposes of comparing the various components of the Wall. Details of how to use these two systems are included below. Google Maps, meantime, looks up the KMZ file here on Per Lineam Valli and interprets it for you in two dimensions.
Google Earth
The following illustration gives some idea of what to expect from Google Earth:
This is version 1.1 and if you have any comments, suggestions etc, then let me know (but beware the spam traps).
Download plv-11.kmz now (95Kb)
Instructions for use
The first thing to note is that layers may be switched on and off in Google Earth's Sidebar. The available layers are: ditch (mauve), curtain wall (red), turf wall and its components (violet), turrets (red, small square), milecastles and gateways (red, medium square), forts (red, large square), Military Way (ochre), Vallum (maroon), Cumbrian coastal system and outpost forts (green), temporary camps (red and black medium square), hinterland forts (lilac, large square), and things to see.
Select a layer using the tick box (obviously, if it is ticked, it will be visible). Click on the small '+' sign in a box and the various components of that layer will become visible. It is also possible to turn these individual components off and on as is required.
Clicking on a component will reveal a Bubble with information about the site (although this is not usually true of linear elements). The marked-up source of this information can be reached by right-clicking on a component and selecting Properties. Additionally, double-clicking on a component will take you straight to it, usually at a height of 1000m, and you may then zoom in or out as you require.
Selecting the Test Flights layer will provide a flight along the Wall. Instructions for configuring Google Earth to enjoy it at its best are contained in that layer. Don't forget that you can fly along the Wall of your own volition (!) by typing CTRL-ALT-A for Google Earth's inbuilt flight simulator (from version 4.2 onwards), where you can use your mouse (or even a joystick) to control your journey.
To keep a permanent copy of the file, right click on the HADRIAN'S WALL v.X level and select 'Save to My Places'. Remember to check back here for updates.
Google Maps
This is a two-dimensional interpretation of the data in the Google Earth file. What it lacks in graphical gimickry, it more than makes up for in terms of portability and accessibility. Theoretically, this means that by using Google Maps for Mobile you could examine it whilst actually walking the Wall but we'll let you know about that once it has been road- (or Wall-)tested.
Microsoft Virtual Earth (maps.live.com)
These Virtual Earth Collections are converted from the original Google Earth KMZ file mentioned above. They will work in 2D in most operating systems and on some browsers (notably Firefox), but in 3D only in Windows. As mentioned above, they have had to be split up into thematic sections due to the limit of 200 items in a Collection (making it currently impossible to include all elements of the Wall system in one Collection). Selecting one of the links below will open it in a separate window (or tab, depending upon how your browser is configured).
