BAJR Federation Archaeology

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I am not too familiar with the ins and outs of GPS. Can anyone suggest a good, easy to use, cost-effective (ie. that won't break the bank) model that would be accurate enough for field survey?

Thanks in advance



This is the one I use in the field, from Jordan to Croatia.. from Scotland to Emirates. has been good enough to track walls and features to 3m accuracy. add it to something like OziExplorer and of course QGIS for the GIS capability. and you have a sound system for retrieval. Strangely I am working on it right now.

You can pick one up from ?170 for example

Its the best gps for me. at a cost that is not too vicious. :face-approve: robust... and easy to use.
Thanks for the link. Do you think it will work in exotic locations like Leith or in a Cardiff hairdressers? Price is within what I was prepared to fork out as well. Cheers.

Think you will be fine in Leith.. ! Smile though it may get stolen and used to buy a q Smile
We've also used this Garmin as standard kit around Scotland (Western Isles to Dunbar) and as with BAJR have found them to be good, standard GPS for low quality (ie we quote 5m) data grabs. They're a good buy to have shoved in a standard kit bag, we bought mapping for one - never found this so useful as quite coarse.
Yes forget the mapping... what you can do is load up the fab contour data created for the Scottish Mountaineering Club I do use that... and its free!

Agree with Manu... THe accuracy is at best 3m however 5m will be a good day... and that means that your point is within a 10m circle so fine survey it ain't. On the other hand, you next step is this... MobileMapper CX rugged handheld GPS receiver with sub meter accuacy.. though this is going to cost about 1800 quid.
and then of course, if it really matters, you can hire this beuaty... but you need special training and software. MMMMMMmmmm the Leica 1200 RTK GPS which I was using to accuracy of +/- 2-3mm that said it will set you back 20k

But you can hire for only about 3-400 quid a week
You can get a Leica 1200 kit for ?20,000? Thats come down a lot in price from the ?30,000+ last time I looked.....snap it up I would say. Fantastic kit and as accurate as you say.....Garmin a good large range GPS at reasonable price. Just don't be looking to locate small finds or grid pegs.....

However bearing in mind the recent free availability of OS map data in the UK (and having something of an obsession at present about not allowing archaeological boys to play with survey toys until at least they demonstrate a sound knowledge of what the toy does or doesn't do!!), I wonder if accuracy with GPS is any grater than you would get with putting a dot on a printed map. I think I could get pretty close to smaller than 5m with a reasonable scale map and sound map-reading/prismatic compass skills. Infact using digital vectorised 'free' maps I have been able to get down to less than 10cm without the use of GPS (checked back for accuracy with total station at later date...)
I have my doubts about handheld GPS, particularly the cheap models. I've seen many cases of GPS points that are wildly out - up to 20m in some cases. I've also seen the trace from a colleague's GPS that was left in a van overnight - it wandered around a 10m radius. And yet I have seen these handheld GPS units being used to survey in site extents and even trench locations! I totally agree with Kevin that a competent surveyor could probably achieve similar or better accuracy using more traditional methods, a possible exception being thick woodland. But surely in any event a cheap handheld unit should never ever be used for anything more than a very broad-brush walkover?
I think the missus would be a bit cheesed off if I spent 20k on one (and how many diggers have that much spare dosh kicking about anyway?), now matter how good it it is. 3-5 metres is fine for what I intend, namely, the give a co-ord for 10m field walking squares and for laying down a couple of grid pegs on remote upland areas where there are no benchmarks. (I figure that as long as the features plotted based on theseTBM's were accurate, then on the whole, I have nowt to worry about). Reason for wanting a GPS is that I want a GPS equipped TST but due to budget, am trying to do it on the 2nd hand TST and a handheld GPS are what I am going for. After the rent has been paid Smile
Hand held GPS is fine for this then, as you say, things are determined by the buget anyway. It depends at what scale you're going to plot at anyway; at 1:5K 3-5 metres is not noticable anyway. Although there is inaccuracy, it is still more of less accurate to itself, so points on the screen 10m apart are likely to be 10m apart in reality. So your survey will be internally accurate, rather than precisely fitted to the National Grid. Hand held GPS is a bit more inaccurate with heights than with X and Y co-ords. Though as sheep says, the locational fix will wander over time, as the satellites come in and out of view. There might be a way around this, like using canes to mark out, and then taking points all at once.
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