Is the NVQ worth it?

[kevin wooldridge]

Putting Total Station data or high accuracy GPS data into a GIS data base is a completely different ball game. Do you do this, if so do you classify the accuracy of the data. Point being locating a target below ground using handled data will be hit and miss. Trying to locate a target underground with data from a total station may be spot on or it could be in another country altogether. What are the checks and balances?

Putting high accuracy survey data into a GIS database is simplicity provided that you survey to an appropriate degree of accuracy and you are using an appropriate interface software bewteen the raw survey data and the GIS programme. Personally I prefer to create shape files, but of course other people like to download into a Cad version and then upload into the GIS. Horses for courses. Of course lots of information gets inputted into GIS systems at different degrees of complexity (I would say that 'accuracy' is a misnomer in such circumstances. A total station is as accurate as you allow it to be. I would normally say for archaeological purposes that 10mm spatial accuracy is reasonable for most archaeological applications) and of course lots of archaeological GIS-data becomes more complex the greater the number of attributes and attribute distinctions that are applied to it. But for the most part that is post-excavation rather than field survey work.

I don't really understand the point about below ground accuracy. I mean a total station is accurate in all 3 dimensions.....If a total station knows where it is, it can find any point within its view. It can give relative levels of depth providing the machine is set up to a known height. There are modern aids to GPS location integrated into total stations (the Leica 1200+ series for example) that do away with the inaccuracies of hand held GPS. Of course there are some areas where sattelite coverage is not so hot (deep forest for example) but even then modern total stations can use a combination of fixed and temporary stations linked to sattelite or celluar and Bluetooth technology to enable most parts of the UK and western Europe to be within reasonable range....

Checks and balances? First task of the day is always to log the control points that the machine is referencing - at least that tells you whether you are in the right field. I have surveyed both sides of Hadrians Wall on a single site so I guess I could have made an error and been in the wrong 'country'.....yes of course things occasionally go wrong (especially when a total station is being used by a number of users as happens with some modern archaeological digitial recording systems), but I am never more than one 'session' (morning til breakfast, breakfast to lunch, lunch till end of day) ever away from a back-up and a resetting of the machine and I always keep a written survey log, so at least any errors can be lessened or points resurveyed. And of course with the advent of Bluetooth I can back-up the memory card of the machine to my mobile phone at any time....I don't think there is any great mystique to archaeological surveying. Modern machines make it relatively easy. I think it's more important for an archaeologist to possess the knowledge of how the measured data can be processed, applied and interpreted rather than a deep understanding of the workings of the machine that does the measuring.