[GRASSLIST:2632] Re: Extracting transects from sites

[Radim Blazek]

On Saturday 14 February 2004 02:17, Hamish wrote:
> > I have a huge sites list derived from side-scan sonar data. There are
> > millions of UTM coordinate pairs and their corresponding depths.
> >
> > I'm going to interpolate this dataset but I want to extract some
> > transects from 'real' data to cross-examine to grid derived data.
> >
> > In a few words, I need to extract all (x,y,z) triplets from my sites
> > file that lies along a dozen lines and are not farther than 100 meters
> > from this line.
> >
> > Does anybody have any clue?
>
> In GRASS 5.7, make a vector line (either by hand with v.in.ascii, or
> s.in.ascii->v.digit to connect the dots), run 'v.buffer buffer=100',
> then [v.select, v.extract, or 'v.overlay op=and' ??] to extract only
> points within the buffer.
>
> Not sure how to do it in 5.0 or 5.3, maybe after creating the vector
> line use v.to.rast and r.buffer. Then use the r.buffer map as a MASK,
> maybe by modifying s.out.ascii somehow?

Or v.distance.

Radim