[GRASS5] Fw: d.area progress report...

[Radim Blazek]

On Friday 25 January 2002 03:05, Eric G. Miller wrote:
> On Fri, 25 Jan 2002 14:08:43 +0100, Radim Blazek <radim.blazek at wo.cz> wrote:
> > On Tuesday 22 January 2002 17:39, Eric G. Miller wrote:
> > > It might be useful.  I understand already the general scanline
> > > conversion (which GRASS does via G_plot_polygon).  However,
> > > G_plot_polygon can not handle eliminating nested areas/holes.
> > > What I'm doing is breaking up the exterior with interiors
> > > such that a set of simple exterior polygons (no holes) are
> > > formed.
> >
> > I use G_plot_polygon in d.vect / g51 and it works (checked also for
> > island attached to area by line going through that island). What is the
> > problem with G_plot_polygon?
>
> Hmm, how did you put the data together?  I tried appending island/hole data
> to the exterior and got a mess.

Very simply, from last point of area to first of isle and from last of isle 
back to last of area. But I have tested only with simple data and some
problems may occure later. But in that case I would prefer improvement of
G_plot_polygon. You can see the code in d.vect / g51. (And test in grass51)

Radim