[GRASSLIST:918] Re: Planning swath bathymetry surveys

[Hamish]

> I've simplified my script a bit based on Hamish's suggestions. But I
> still can't figure out how to get the vector areas to equal the vector
> boundaries. I have messed around with v.clean a bit, but haven't
> stumbled on the solution yet.

making sure all cat numbers are the same and then using 'v.extract -d'
doesn't work??

v.overlay instead of v.patch in a loop?


> Here is an update to the script and
> another picture of what I am writing about:
> 
> http://pages.google.com/edit/david.p.finlayson/swathwidth

doesn't work (we can't edit^^^ your page)

 
> For my problem, buffering the nodes with circles means that the buffer
> is working both normal to my line (which is what I want) but also
> parallel to my line which is not ok for my application. Swath beams
> don't spread out in a circle, they are thin rectangles. So, the
> planning tool I am working on will overestimate the swath coverage
> when the survey crosses from deep to shallow water (or vis-a-vis).

what if instead of v.buffer you use v.mkgrid, 1 grid box long & thin
with appropriate angle= setting? Maybe make two symetrical grid boxes,
one each side of the track line to make the origin easier to calculate.


Hamish