Mapping software options

[stef]

The trouble was recording feild boundries with large trees along the hedges causing signal loss. I don't have may feilds I could drill the first time around without loosing signal at least once.

Yes, I understand the recording issue.
But, you will not be able to follow a "predefined" line (build at your desk) for the same reasons (signal loss), no?

 

[clbarclay]

Having got most boundries in near enough the right places now I can use them to set the headland tramlines, better section control, give a more accruate figure for cropped area and can now drill from the inner pass outwards. If I am drilling the headland after the middle of a field I have drilled once around first giving a clear mark to work to. I still have to manual steer in places, but its kept to a minimum. Only small savings, but helps eliminate some irritating errors.

 

[Pheasant Surprise]

That will depend how far they zoom in and how accurate the satalite images align to gps coordinates. I have a margin around most fields so can accomidate a slight error.

It would have to be pretty crude to be worse than the errors I get recording in fields when the correction times out or too many saterlites are obscured.

Definitely the most accurate mapping will be that which you've recorded and generated with your own gear in your own fields, and then use in future.

I've compared "official" Ordnance Survey MasterMap field boundaries and features (as on licensed by DEFRA, the RPA, MAGIC etc.) and although they are generally pretty accurate they are certainly not as *absolutely* accurate (as in precise grid position) as you might first presume or expect.

I've found some boundaries and features to be out by 2 metres or more: 33 kV power poles in fields were more than 2.5 metres "out" on an RTK survey compared to where OS MasterMap said they were.

I was pretty shocked by this - I mistakenly thought MasterMap Topography maps were "survey grade", but if you read the fine print the accuracy tolerance margin is something like 2.4 metres @ 2500:1 (with most farmland in UK mapped at this scale)

I certainly wouldn't recommend converting/building a shape files purely from online sources and relying on everything to be in the right place...certainly not if obstacle and ditch avoidance was important.

Measuring and defining your own boundaries first would be the most reliable basis.