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Google not helping.
so what's the total boundary length of Gloucestershire (or how to calculate it)?
This chap looks up have tried to walk the perimeter of Gloucestershire. Although I doubt that he followed the precise boundary and probably stuck to roads and paths/bridleways. Claimed by him to be 300 miles.
Even if you could somehow find the data, it's not as easy a question as you might imagine. It's all down to the resolution of your mapping and weird stuff that goes on when you look closely at fractals.
As above. Remember watching and interesting piece looking at this with regard to the coastal perimeter of the country.
Yes but a man made boundary like this is not like a coastline, so that is not relevant.
If you get the boundary in some standard GIS format (maybe https://www.ordnancesurvey.co.uk/business-government/products/boundaryline)
then with a bit of hacking you might be able to get the length using a tool like qgis
Measure it fine enough detail and it becomes of infinite length.
found this map on the county council website which very handily includes the perimeter as a vector line:
if I load it into Illustrator and scale it, then turn it into a polygon, it'll automatically give me it's perimeter length.
as above - it's very jaggedy though, so possibility overstates what the length [I]actually[/I] is if you were to walk it for example. I added some smoothing so the line looks less ridiculous and the figure is 245 miles.
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Yes but a man made boundary like this is not like a coastline, so that is not relevant.
Weeeeellll, that's true if it's like the Canada-US border which is (in large parts) just a straight line drawn across a map - in this case, the 49th parallel. But I'm guessing that the border of Gloucestershire follows natural stuff like rivers/ streams which are subject to exactly the issues discussed.
found this map on the county council website
Which doesn't appear to include South Gloucestershire...
So are we talking Shire County or Ceremonial County perimeter? 😉
424961.443283m (264.058799 miles which aligns with the above)
This is the boundary of the Gloucestershire County polygon in the OS Boundary Line dataset linked to above where the spatial reference system is British National Grid.
Incase you're interested the area of the same polygon in Hectares is 270452.850741742.
D
I'm guessing OP is not an ant nor a turtle with a world on it's back. HTHs.
424.8 km according to that OS download
I do not know that the definition of a country depends on natural features. Maybe there are multiple definitions for different purposes, some traditional, some modern. Be a bit odd that with a bit of erosion someone could find their house changing county.
(edit: ahhh too late)
I don't have either to hand but I'm sure someone could have a pretty solid bash at measuring it with a scale map & piece of string.
I’m sure someone could have a pretty solid bash at measuring it with a scale map & piece of string.
I've just measured it with a piece of climbing rope and a UK atlas, and I can tell you it's about 50 miles.
what an odd setup! Must be some strange people living there for sure! 😃Which doesn’t appear to include South Gloucestershire…So are we talking Shire County or Ceremonial County perimeter?
Anyway, the wikipedia article on S Glos. includes that bit highlighted as an SVG (vector) file, so I added it on to the original map, new figure is 263 miles.
Ahhh gotta love fractals...
llama, I see what you are saying on refining scale - it's not like a beach that could be refined down to grains of sand... but what about on larger scales? The boundary will have a legal definition based on e.g. the centre of a river at a certain point in time, and so an agree location. Ignoring the spatial drift depending on your reference frame. If you measure that at the order-1-m scale then you'll get one answer, but if you 'zoom out' to the planetary scale you would smooth the vertices and get a different number. That's all people are pointing out, that the distance depends on the scale you are looking at, and yes of course measuring to the order 1 to 100 m is sensible and the answer has been given above.
Yes you are right - the real question is - exactly what is the border and how is it defined?
Is there direct reference to natural features? In which case, fractals, which are much more interesting than polygons.
Yes you are right – the real question is – exactly what is the border and how is it defined?
Is there direct reference to natural features? In which case, fractals, which are much more interesting than polygons.
Because I was interested, I went on a Google mission and came back with this interesting document. It's from 1986, so I wouldn't expect it to be completely up-to-date, but equally I'm sure that much of that boundary remains.
It looks to be a complete mishmash of boundaries defined by, variously, rivers, roads and field boundaries. In some places there are boundary posts, which presumably could be used to plot straight-line boundaries.
If you had the patience, you could use the "measure distance" function on Bing Maps and draw round the border. It's quite a wiggly one though, isn't it
Walk it.
And be a poseur by using the word ‘ambitus’.
HTH.
Thanks all!
I knew you wouldn't let me down 🙂
I’ve just measured it with a piece of climbing rope and a UK atlas, and I can tell you it’s about 50 miles.
I lolled
😆
It has klong been my plan to cycle it. Can't decide on the rules though. Nearest road? Nearest road purely wit the county? Shorter than I thought though.
Pretty sure it's not a fractal because it's a line on a map.
Measure it fine enough detail and it becomes of infinite length.
Also don't think so because as you zoom in each extra fiddly bit you add is smaller and smaller. Something to do with Hausdorff Beiscovitch dimension that I've forgotten
Could the map being taken in to Photoshop, delete the background compare the two and deduce the perimeter somehow ?
Ilustrator , Xara or something.
Just pondering.
fractals, which are much more interesting than polygons.
Ooh, that’s somewhat controversial. I love a fractal, but polygons can be very interesting - surely some are fractals.
I think to answer how long is the perimeter of Gloucestershire, it helps to know what you intend to do with the answer.
"it helps to know what you intend to do with the answer"
someone on Twitter thought I might be able to help. Not sure why, tbh, but it's good so far!
Assuming some of the border is defined by the centre point of a river for some part of the border, then the border is a fractal by definition and you can't measure it. Borders defined by rivers change all the time... Any polygon you get from OS will just be the approximate perimeter.
Or you could just google "circumference of gloucestershire" 😉
https://ukga.org/index.php?pageid=14 suggests 245 miles.
circumference? Lumme I'd tried every variation on boundary I could think of but not considered it as a circle 🙂