4 ms·

In the UK (technically Great Britain in this context) at least, there is an open dataset available from the national mapping authority (Ordnance Survey), which

by g_p 5y ago

In the UK (technically Great Britain in this context) at least, there is an open dataset available from the national mapping authority (Ordnance Survey), which is called boundary lines. It contains all of the different boundary lines and borders of local authorities, parliamentary constituencies, regions, nations etc. This is all geo referenced against the OSGB coordinate system. I could see interesting challenges in doing this for international borders where both countries use different coordinate systems and projections for their mapping, and the potential for slithers of no-mans-land. I guess at a certain point, you need to refer back to what's on the ground, as over decades the land erodes from the sea, and rock formations collapse and shift as the earth moves etc. The definition of location gets far easier when you have satellites offering precision navigation and timing!

NelsonMinar 5y ago
Are those boundary lines the actual legal international definition of the borders? Or is it just some convenient representation close enough for ordinary uses? You'd think location via GPS or similar framework was easy but it's not nearly as easy as you'd think. Among other things, the land is moving. Both continental plates and then also local features like river beds. See e.g. https://www.youtube.com/watch?v=_TX--Fku9NQ https://www.youtube.com/watch?v=_TX--Fku9NQ
mnw21cam 5y ago
The OS maps the borders of local authorities. However, it doesn't hold the authoritative map of the borders of the counties. I don't mean the modern local authorities that call themselves counties - I mean the traditional counties, which haven't been abolished or changed for centuries. The exact location of these is defined almost tautologically - a place is part of a certain county because it has always been. The exact location of the border is more a matter of folklore than anything else. Likewise, the exact location of borders between properties is usually ill-defined. Only borders that have gone through a painstaking process of surveying and registering (usually after a dispute or on a new build) are exactly defined. Usually, when you move into a new house, you have a fence around your property, and the boundary is generally assumed to be inside the fence (with conventions for whose land the fence sits on that aren't always followed). Adverse possession makes it more complicated. A neighbour decided to put up a new fence, and weren't nice about it. I stipulated (in line with the law) that no part of the new fence could be placed on my property (except parts under the ground surface). They decided to put the fence in the "wrong" way round, with the vertical posts on their property, and the fence attached on their side of the posts, effectively giving me sole access to the area of land in-between their fence posts. If I were to sell my house, the new owner would be quite reasonable in assuming that that land was theirs. After the requisite time, I could apply to have the land legally registered as mine, although the new laws mean that the neighbour would be informed and given a chance to "evict" me from the land - they would have to tear down their fence and rebuild it the right way round so that I don't have sole access to it any more. In this way, adverse possession effectively resets the boundary to where the actual fence is in practice every now and again, which means that the land registry doesn't need to store exact boundary locations.
- pacaro 5y ago
  My parents' house is a good example of this. The rear boundary of the property is defined as being some distance from the road. It's not totally clear (although I assume that there is a standard) whether this means the curtilage or something else. When the land behind the property was redeveloped (from a run down witches cottage to a block of flats) it was important to my parents that the treeline at the rear of the property not be cut down. The deciding factor was the rusted remains of an old fence on the far side of the trees. I had been under instructions as a kid to not mess with that or pull it up because my parents knew that it was important to preserve this kind of evidence
iso1631 5y ago
In the UK, most freehold boundaries are available as a gml file. I'm looking at moving house and have one open right now in fact, here's a screenshot of it https://imgur.com/cX2Seow.png https://imgur.com/cX2Seow.png The white area being roads and non-registered land (mainly stuff that hasn't sold for decades and roads). It's great, I can find a unique owner for any bit of field I have a question about, the size of the plot, etc. The downside is that to get a copy of the actual entry in the register (to see who owns it and any covenants on the property there are), you have to pay £3. The entire process is digital and automated, IMO it should be free, but I suppose it's not a terrible price.
- simpss 5y ago
  it has a small price so it becomes difficult/cost-prohibitive to use for nastier purposes. ex, in my country forest owners get spammed and targeted by forest-management companies that want to cut it down.

by g_p 5y ago

NelsonMinar 5y ago

Are those boundary lines the actual legal international definition of the borders? Or is it just some convenient representation close enough for ordinary uses? You'd think location via GPS or similar framework was easy but it's not nearly as easy as you'd think. Among other things, the land is moving. Both continental plates and then also local features like river beds. See e.g. https://www.youtube.com/watch?v=_TX--Fku9NQ https://www.youtube.com/watch?v=_TX--Fku9NQ

mnw21cam 5y ago

The OS maps the borders of local authorities. However, it doesn't hold the authoritative map of the borders of the counties. I don't mean the modern local authorities that call themselves counties - I mean the traditional counties, which haven't been abolished or changed for centuries. The exact location of these is defined almost tautologically - a place is part of a certain county because it has always been. The exact location of the border is more a matter of folklore than anything else. Likewise, the exact location of borders between properties is usually ill-defined. Only borders that have gone through a painstaking process of surveying and registering (usually after a dispute or on a new build) are exactly defined. Usually, when you move into a new house, you have a fence around your property, and the boundary is generally assumed to be inside the fence (with conventions for whose land the fence sits on that aren't always followed). Adverse possession makes it more complicated. A neighbour decided to put up a new fence, and weren't nice about it. I stipulated (in line with the law) that no part of the new fence could be placed on my property (except parts under the ground surface). They decided to put the fence in the "wrong" way round, with the vertical posts on their property, and the fence attached on their side of the posts, effectively giving me sole access to the area of land in-between their fence posts. If I were to sell my house, the new owner would be quite reasonable in assuming that that land was theirs. After the requisite time, I could apply to have the land legally registered as mine, although the new laws mean that the neighbour would be informed and given a chance to "evict" me from the land - they would have to tear down their fence and rebuild it the right way round so that I don't have sole access to it any more. In this way, adverse possession effectively resets the boundary to where the actual fence is in practice every now and again, which means that the land registry doesn't need to store exact boundary locations.

pacaro 5y ago
My parents' house is a good example of this. The rear boundary of the property is defined as being some distance from the road. It's not totally clear (although I assume that there is a standard) whether this means the curtilage or something else. When the land behind the property was redeveloped (from a run down witches cottage to a block of flats) it was important to my parents that the treeline at the rear of the property not be cut down. The deciding factor was the rusted remains of an old fence on the far side of the trees. I had been under instructions as a kid to not mess with that or pull it up because my parents knew that it was important to preserve this kind of evidence

iso1631 5y ago

In the UK, most freehold boundaries are available as a gml file. I'm looking at moving house and have one open right now in fact, here's a screenshot of it https://imgur.com/cX2Seow.png https://imgur.com/cX2Seow.png The white area being roads and non-registered land (mainly stuff that hasn't sold for decades and roads). It's great, I can find a unique owner for any bit of field I have a question about, the size of the plot, etc. The downside is that to get a copy of the actual entry in the register (to see who owns it and any covenants on the property there are), you have to pay £3. The entire process is digital and automated, IMO it should be free, but I suppose it's not a terrible price.

simpss 5y ago
it has a small price so it becomes difficult/cost-prohibitive to use for nastier purposes. ex, in my country forest owners get spammed and targeted by forest-management companies that want to cut it down.