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gypcaver wrote:What is the footprint of a cave? Or another way of wording it is, "what area does a cave lie under?" Can we determine the "footprint" by using the plan view of a cave map? I have an idea of what I mean by the footprint, but I'm interested in hearing how others would define the footprint.
gypcaver wrote:What is the footprint of a cave? Or another way of wording it is, "what area does a cave lie under?" Can we determine the "footprint" by using the plan view of a cave map? I have an idea of what I mean by the footprint, but I'm interested in hearing how others would define the footprint.
gypcaver wrote:I propose that the footprint should be defined as the smallest convex polygon that encloses the horizontal extent of the cave. One can visualize this as a rubber band or string stretched around the plan map. The vertices, or corners, of the polygon would be at the ends of the remote passages of the cave. This definition is easy to understand. The area of a complex polygon is fairly easy to compute, if one knows the coordinates of the vertices, and it seems to fit what one would mean by the footprint.
Extremeophile wrote:gypcaver wrote:I propose that the footprint should be defined as the smallest convex polygon that encloses the horizontal extent of the cave. One can visualize this as a rubber band or string stretched around the plan map. The vertices, or corners, of the polygon would be at the ends of the remote passages of the cave. This definition is easy to understand. The area of a complex polygon is fairly easy to compute, if one knows the coordinates of the vertices, and it seems to fit what one would mean by the footprint.
I'd support this definition. Maybe you could send an email to Larry Fish and see if he could incorporate this calculation into Compass. This might also make an interesting Convention discussion topic.
The only practical concern I have is where to find rubber bands big enough.
Marlatt wrote:Extremeophile wrote:gypcaver wrote:I propose that the footprint should be defined as the smallest convex polygon that encloses the horizontal extent of the cave. One can visualize this as a rubber band or string stretched around the plan map. The vertices, or corners, of the polygon would be at the ends of the remote passages of the cave. This definition is easy to understand. The area of a complex polygon is fairly easy to compute, if one knows the coordinates of the vertices, and it seems to fit what one would mean by the footprint.
I'd support this definition. Maybe you could send an email to Larry Fish and see if he could incorporate this calculation into Compass. This might also make an interesting Convention discussion topic.
The only practical concern I have is where to find rubber bands big enough.
I've actually done this some time ago, using the .sta file which Compass can generate from survey data. At one point, I was trying to compare areal densities (total survey length / footprint area) for various caves in my database. Like most of my projects, however, this has been neglected due to competing priorities. I might be able to find my code somewhere...
Stuart
gypcaver wrote: I propose that the footprint should be defined as the smallest convex polygon that encloses the horizontal extent of the cave.
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