OpenStreetMap 開放街圖
While editing a local park I noticed how the meanders of a creek differed from the meanders from the satellite view. I assume it was mapped long ago when the satellite view was different. Here’s what it looks like. It would be cool to see when the map and satellite views were created to find out how long it took for the changes in the stream’s course to be made.
Let me know if you find any other examples of this interesting anomaly.
討論
由 ke9tv 於 2022年02月24日 14時46分 發表的評論
Locally to me, many of the small streams in the lowlands change every spring when the snow melts. Some of the third- or fourth-order rivers have changed course significantly in major storm events; in particular, Hurricane Irene in 2011 caused several small rivers in the Catskills to cut new channels.
An interesting side point is that cadastral boundaries often follow the former alignment of watercourses. American law is complicated there; what happens with property lines and political boundaries depends on the process by which the water moved - was it a gradual event or a sudden catastrophe, and did it move from a force of nature, or from human intervention? The field abounds in obscure legal terms: accretion, erosion, avulsion, reliction, and so on.
Don’t even get me started on what happens in beaver habitat! It took me half an hour to walk around this mess, where the beavers flooded the trail (and several hundred metres upstream).
由 andy mackey 於 2022年02月24日 21時35分 發表的評論
I noticed a few ago that a parish boundary followed the route of boggy bit in the field that I remembered from 1952 .and realised the river line had probably been moved when they had constructed the lock. It is easier was easier to build the lock on dry land then divert the water through it. I noticed similar situation when the A14 road Cambs UK 2015 2021 was built. New bridges across the new A14 were built adjacent to the old roads together with the linking roads and over night the road was sent over the new bridge causing little or no delay. This old Roman road was once straight but now kinks a little. see osm.org/?mlat=52.2923&mlon=-0.1490#map=15/52.2923/-0.1490 I have mapped a lot of footpaths in the last almost ten years. When I walk the path again I’ll re-check against my GPX and Bing and maybe edit them. I can inspect the date of the mapping to see when if and when I edited before. I use the Potlatch editor to do this. I’m don’t know if older Satellite or Ariel are available. You could ask in the Help Forum. Happy Mapping Andy