Re: [talk-au] Why set coast line to nation park or, administrative boundaries?
On 29/3/23 14:30, Andrew Harvey wrote: On Wed, 29 Mar 2023 at 14:05, OSM via Talk-au wrote: Since the coastline tag is also supposed to represent the high water mark then I would say that they should be snapped together (since they then represent the same feature - that is, the high water mark). This would mean that the boundary data already in OSM from the government basemaps would just be their own mapping of the high water mark, and probably be less up to date or refined as our own. Exactly. So if anything we should be actively snapping them. In Victoria, from a very interesting document "THECOAST AND THECADASTRE" AReport for the Victorian Environmental Assessment Council August 2019" Unfortunately it is a PDF download only .. and I cannot get a direct link so search for the above "Victoria the Coast and the Cadastre" I quote from here on from the document, I do recommend reading all of it if your interested in these 'ambulatory boundaries'. - Detail of the plan defining Cape Conran Coastal Park2. The inland boundary follows geometrically well-defined lines, and is fixed in position. North of the inland boundary is freehold land. The seaward boundary of the Park is ‘Low Water Mark’ and hence is ambulatory. South of the seaward boundary (i.e.Bass Strait) is unreserved Crown land. Topographic features may move, and ambulatory boundaries may move in response under the common law doctrine of accretion. The doctrine is well established internationally, but has resulted in very little Australian case law, so we have come to accept Surveyor Generals’ rulings as beingde factoexpressions of the common law. TheLocal Government Act 1989, section 3(3A) states: “if a boundary of a municipal district is described by reference to the seacoast (regardless of whether it is referred to as the Sea shore or the waters of the sea or a bay or in any other way) that boundary is to be taken to be the line for the time being of the Low Water Mark on that sea coast”. the surveyed sea boundary is defined only at that date. The sea boundary is still subject to change due to gradual and imperceptible movement. The fundamental concepts (snip) 1The legal boundary between tidal waters and adjacent land is the High Water Mark (except where the sea boundary is otherwise defined). (snip) 6Land below high water mark (or other sea boundary) belongs to the Crown - There are statements about; the high water mark being used for both private and 'public' land the 'foreshore' being council land The report suggest that climate change will make things difficult and that the government should 'make changes'. My pessimism says that they will make no changes until things get much worse. ___ Talk-au mailing list Talk-au@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Why set coast line to nation park or administrative boundaries?
On Wed, 29 Mar 2023 at 20:25, Warin <61sundow...@gmail.com> wrote: > > As for the administrative boundaries .. the present official view is > that local councils cannot now sell 'land' between the high tide and low > tide, however they have in the past. > > What the state of this 'land' between high and low tide is now I'm not > certain of. > Several years ago now, I was having this same conversation with a bloke from Sydney. His family have owned a private marina in Sydney (I'm not sure if the main or Middle Harbour?) since the mid-1800s. They have a car park on the shore, a jetty going out over the water, with their office built on it, & a pier going further out from that. Several years before I was speaking to him, they'd put in for planning approval to rebuild & extend the existing office on the existing jetty, where it's above the actual land / water boundary. Council had no issue with it, but they were still waiting State Govt approval, as the two departments involved (call them Lands vs Harbours & Marine) were arguing, *in court !*, over which Dept had the right to give them the OK to go ahead! NB neither Dept had any issue with the planned work, they were arguing over which of them had control of that bit of wet dirt, 2m below the jetty, which hasn't seen the light of day for 170 years!, & which wasn't going to be touched, or affected in any way, by the proposed work :-( Thanks Graeme ___ Talk-au mailing list Talk-au@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Why set coast line to nation park or administrative boundaries?
On 28/3/23 20:46, Frederik Ramm wrote: Hi, I would advise caution with this. Government bodies will typically hold their own GIS data for park boundaries or administrative boundaries, and the GIS data they have will never fully align with the coastline. However, it is not our job to be an agent for publishing government data. We have to look further and ask for the actual situation. If the national park boundary is mostly along the coastline The problem arises that OSM uses the high tide mark for the coastline ... there is the possibility that National Parks use the low tide mark - so they cover anything washed up on the beach. The official government data looks to me to use the low tide mark. I have sent an inquiry to the National Parks people in the state of interest. As for the administrative boundaries .. the present official view is that local councils cannot now sell 'land' between the high tide and low tide, however they have in the past. What the state of this 'land' between high and low tide is now I'm not certain of. ___ Talk-au mailing list Talk-au@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Why set coast line to nation park or administrative boundaries?
On 28/3/23 22:06, Little Maps wrote: Slightly different issue… but the accuracy of governmental admin boundaries can vary a lot depending where you are in Aus. In regional NSW, allotment boundaries (and associated park, state forest and local gov boundaries) as shown on the NSW gov base map (and as often used in OSM) are often inaccurate by 20-50 m and sometimes lots more. This inaccuracy is clearly stated on the Six Maps FAQ page (see Q 6&7). I too have found inaccuracies with respect to their own imagery. Where I have come across it I have used whatever data is present in OSM and offset the base map to match that. This could have been sourced from bing or any other imagery but at least the map will be consistent in what ever offset it has in that area. ___ Talk-au mailing list Talk-au@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Why set coast line to nation park or, administrative boundaries?
On 29/3/23 14:30, Andrew Harvey wrote: On Wed, 29 Mar 2023 at 14:05, OSM via Talk-au wrote: Since the coastline tag is also supposed to represent the high water mark then I would say that they should be snapped together (since they then represent the same feature - that is, the high water mark). This would mean that the boundary data already in OSM from the government basemaps would just be their own mapping of the high water mark, and probably be less up to date or refined as our own. Exactly. So if anything we should be actively snapping them. I believe this is wrong. For example in NSW... From https://rg-guidelines.nswlrs.com.au/deposited_plans/natural_boundaries/consents_naturalboundaries "However Crown Lands is not the only owner of land below MHWM. Where Crown Lands is not the owner of land adjoining the foreshore, consent must be obtained from the appropriate authority. Some of these include: * National Parks and Wildlife Service (where tidal waters have been included in land resumed for state or national parks)" This is my first time responding on talk-au, lmk if I've messed up any formatting to link to the original question. Welcome! The content looks fine to me. ___ Talk-au mailing list Talk-au@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-au
