Anyone used a tablet with GPS?

[Tim Lund]

I was in a committee meeting of the Albion Millennium Green last night, and the question came up of getting a tree survey done. I think I could identify most trees, so it struck me all I would need to do it was a convenient tablet with a GPS receiver, which I could go round with and, standing by a horse chestnut, say, click a button to say 'here be a Horse Chestnut', and then carry on until I'd done all the trees, and other features, such as beginnings and ends of fences, streams and where they change direction.

The main difficulties, I'd guess, were (1) accuracy - but that must just be a matter of whether good enough technology is yet available; if it isn't, it's going to be before too long; and (2) whether the leaf canopy gets in the way of the GPS signal - so hopefully someone can tell before next spring.

It's something I'd also like to do at the Dacres Wood Nature reserve, and in Mayow Park.

If it was on a Microsoft machine with an API, I could write some code to generate maps from data collected, using Googe Earth downloads.

[JRobinson]

you might be interested in TreeZilla then Tim.
This is the idea to capture every single tree in the country - it's a university project, along with some tree related organisations.
what you say about GPS is true - you'd need an accurate one, most that you get as standard are within 10m - you can pay £3k for ones that are to the nearest 10cm. Under tree canopy, and in urban canyons you have issues. You also need to think of the spread of the satelites that your GPS is getting data from - if they're all directly above you, or if they're all near the horizon, the accuracy is less, you need a good spread across the sky for higher accuracy.
I use a Trimble GPS device at work. There is a good GPS tutorial off that home page linked.

The other stuff you mention, streams, and fences, should be covered by Ordnance Survey data, they use satelite images, and on site surveys to get very accurate data. There is also Open Street Map, which is crowd sourced, Open data.

[Tim Lund]

you might be interested in TreeZilla then Tim.
This is the idea to capture every single tree in the country - it's a university project, along with some tree related organisations.
what you say about GPS is true - you'd need an accurate one, most that you get as standard are within 10m - you can pay £3k for ones that are to the nearest 10cm. Under tree canopy, and in urban canyons you have issues. You also need to think of the spread of the satelites that your GPS is getting data from - if they're all directly above you, or if they're all near the horizon, the accuracy is less, you need a good spread across the sky for higher accuracy.
I use a Trimble GPS device at work. There is a good GPS tutorial off that home page linked.

The other stuff you mention, streams, and fences, should be covered by Ordnance Survey data, they use satelite images, and on site surveys to get very accurate data. There is also Open Street Map, which is crowd sourced, Open data.

Thanks again. Would anyone connected with Treezilla be ready to lend me a £3k machine?

The problem with Ordnance Survey with regard to Dacres Wood, at least, is that it was originally just part of a (very large) back garden, so the OS never surveyed it.

I've heard of Open Street Map, and follow them on Twitter. They have monthly meet ups, and I've thought of going along to one, but not got round to it.

[JRobinson]

...
Would anyone connected with Treezilla be ready to lend me a £3k machine?

probably not. they might not even have one. the only way to find out would be to conact them and ask.

The one that I have for my job is only an £800 version, I don't need the accuracy, and before you ask me, no I can't lend it you.

[sparticus]

I have a laptop with a cheap GPS "puck" for marine navigation as a back up system to a dedicated plotter. A lot of people use similar systems with tablets for the same purpose. It uses off-the-shelf navigation packages and I have both a rather expensive proprietory package and a freeware one, which is better. I imagine it is possible to get free-ware programs for terrestrial navigation and mapping as well. The Globalsat puck cost about £35 and uses WAAS positioning. I have always found it perfectly accurate enough for marine navigation, though I appreciate that on water you are in a much cleaner environment signal-wise. (And before anyone draws the inference that this old lefty is in fact a bloated yacht-owning plutocrat, please be assured that I have a very old boat I keep in a creek in Essex)

[Tim Lund]

Just looking at Treezilla, and I notice it uses Google Maps



because it has the pond in Dacres Wood Nature reserve which Michael uploaded. OTOH, Open Street Map, which I'm looking at with the idea of revamping the Joomla site I did some time ago for allotment sites in LB Bromley, does not have this feature



OTOH, Open Street Map in other ways seems to have more information.

I much prefer the idea of using Open Street Maps in the long run, because Google doesn't have copyright of anything uploaded.

If anyone is interested, I just posted about this on an OSM forum, asking for help. If anyone here can also help, that would be cool.

[Eagle]

Sorry Tim the last tablet I had , with or without GPS was paracetamol.