As a volunteer, I'm doing some mapping for the American Red Cross. The idea is to divide northern New England (USA) into response areas for our disaster action teams. Each team covers an area about the size of a county. Each town/city is entirely in one area or another, but the areas do not strictly follow county boundaries. I'm doing the mapping in various ESRI products, and the final result will be posted as a map to ArcGis Enterprise. The final result will be in the web WGS projection.
One issue is what to do about the ocean adjoining towns. We have no need to have a legally-correct town boundary out in the water. I want to draw a boundary that includes all coastal islands, and uses simple shapes that can be presented quickly to readers using web browsers. But I would like to follow practices that won't seem egregiously bad to those who know the real boundaries are.
One simple question is, when I extend a town boundary into the ocean, what azimuth should I follow? If the two towns have a straight line as a boundary, should I just extend it? What if the boundary between the towns is complex, such as the center of a creek?
@ashton I definitely am not an expert on this, but my reaction is that town boundaries do not extend out into the ocean. In the US, each state has a definition for the limit of private or (I think) municipal ownership along tidal shorelines and beaches; beyond that, the land under tidal waters belongs to the state (out to some other limit). These limits are usually stated to be the "high water line" or the "low water line," for some definitions of "high" and "low," or a combination, such as "to the low water line, or to such-and-such distance from the high water line, whichever is closer to the inland area."
As for coastal islands that are considered to be parts of towns, I imagine the same applies. There's probably some ancient statute or act that says a particular island belongs to a particular town, and then the above limits (high water, low water,...) apply around the island.
I'm eager to hear, from people who actually know, whether I'm on the right track!
If it's a straight line I think I'd just extend it out.?ÿ For a line with jogs I think I'd probably just do something perpendicular-ish to the coast.?ÿ As long as you don't split any islands in half then I think you'll be just fine.
@bill-c You are correct as it relates to tidal waters and navigable waterways but that's not necessarily the same with non tidal lakes and streams where the bed of a lake or stream can be privately held.?ÿ I deal with both situations living in an area having a ton of freshwater lakes and streams and working 60 mile away along the Atlantic coast.
DANGER!
It is not at easy as drawing a few lines.?ÿ Here in MA we have perambulation where the Town Officials are supposed to walk the boundaries in common and resolve differences.?ÿ Chatham and Harwich have a line in common that follows the a creek (Muddy Creek, aka Monomoy River, brackish / tidal).?ÿ The area near the shore accreted and the Select Boards decided to follow the creek to a point, then project straight to a point in Pleasant Bay. With the accretion, the creek is now longer and it winds on either side of the boundary.?ÿ There are a series of range poles that mark the boundary for the fishermen.?ÿ You would have to perform some research to find this legally binding and unique resolution.
@spledeus Thanks. Fortunately, we don't need legally correct boundaries. If we can get each road and building in the correct town (even if the building is on an island) that's sufficient. Even the correct town isn't too critical as long as it's in the right state, since our disaster teams routinely respond to each other's response area depending on who's available and the location of the responder's home.
Remember you are dealing with jurisdiction,?ÿ not ownership. A perfectly good application of the relevant shoreline management act may get you the wrong answer.
In this case it would make sense to divide along physical features like access routes, and capture islands the same way. Group the communities rather than corporate limits.
As an aside, i have yet to see riparian or littoral boundaries where extending lines is the right answer. In most cases it is a proportion of frontage on the body in question. This is especially true in the public?ÿ lands States.
All of CT, MA, and coastal NH are incorporated, so just follow the established town boundaries. For Maine just do whatever makes sense, an area is wither inside a town or not, you can't speculate where the boundary would be placed if a nearby town was enlarged.?ÿ
@thebionicman Physical features and access routes are the main reason we are dividing response areas town by town, rather than having counties as our smallest division. And it may end up assigning some islands in the Atlantic according to which town the ferry to the island departs from, rather than what town the island belongs to.
@aliquot So far Maine is divided up on a county basis. If necessary, we could carve a town out of one county and assign it to a different county.
@spledeus - I recall that MA has rights that extended out to MLW or 1600' feet whichever occurred first.?ÿ Is that still the case??ÿ I remember doing a few surveys on the cape where we had to walk out with a rod through the mud flats at low tide until we hit 1600' by stadia.?ÿ Usually those were extensions of the property lines unless described otherwise.
