 Ok, thanks a lot.

I wonder how I could have digitized one segment of length 0 (???)

Anyway, I thank you a lot for your answer. I think it will solve my problem
for the moment.

Best,

Mathieu

2011/9/22 Michael Sumner <mdsumner@gmail.com>

> It seems it is because one of your line segments is of length zero,
> using your attachment:
>
> load("track.RData")
> library(spatstat)
> which(!lengths.psp(track.psp) > 0)
> [1] 17
>
> Dropping the offender:
>
> noZeroLengths <- track.psp[lengths.psp(track.psp) > 0]
>
> (pts <- pointsOnLines(noZeroLengths, eps=50))
>  planar point pattern: 1134 points
> window: rectangle = [865841.7, 888666.8] x [6265115, 6300668] units
>
> You might want to investigate why you have a zero length line segment
> in your original shapefile, there's a lot of options for what you
> might do in R but where you catch it depends on your main goals I
> guess.
>
> I think there are some good suggestions here for catching these cases
> in spatstat and sp, but I haven't looked closely enough yet to say
> anything helpful.
>
> Cheers, Mike.
>
> On Thu, Sep 22, 2011 at 9:00 PM, Mathieu Rajerison
> <mathieu.rajerison@gmail.com> wrote:
> > Thanks for the answer!
> >
> > I coerced my SpatialLinesDataFrame object to a psp object using a non-NA
> > column.
> >
> > Plotting is OK but pointsOnLines still fails:
> >
> >> track.psp <- as(track[, 2], "psp")
> >> plot(track.psp)
> >> pts<-pointsOnLines(track.psp, eps=50)
> > Erreur dans ppp(x = x, y = y, window = win) :
> > all coordinate values are NA or NaN
> >
> > What's wrong?
> >
> > 2011/9/22 Michael Sumner <mdsumner@gmail.com>
> >
> >> The problem is that the first attribute on the track object, "ID" is
> >> NA - and when plot.psp is trying to draw a legend it has nothing to
> >> base the image "ribbon" on.
> >>
> >> This should avoid the error:
> >>
> >> plot(track.psp, ribbon = FALSE)
> >>
> >> Try subsetting the attributes in the coercion to psp, choose which
> >> column you want from names(track) but note that with only one row the
> >> ribbon legend will never be very interesting:
> >>
> >> track.psp <- as(track[,"PREC_PLANI"], "psp")
> >>
> >> plot(track.psp)
> >>
> >> Finally, do include sessionInfo() as requested - you have not let us
> >> know that you require packages sp, rgdal, maptools, and spatstat - and
> >> all of that is very important when determining what is going on.
> >>
> >> Cheers, Mike.
> >>
> >> On Thu, Sep 22, 2011 at 7:29 PM, Mathieu Rajerison
> >> <mathieu.rajerison@gmail.com> wrote:
> >> > Hi,
> >> >
> >> > I Have a problem with a psp object.
> >> >
> >> > I can't plot it, neither perform a pointsOnLines calculation on it.
> >> >
> >> > ---
> >> > Here is what I obtain with my different operations:
> >> >> track <- readOGR("voie.shp", "voie")
> >> > OGR data source with driver: ESRI Shapefile
> >> > Source: "voie.shp", layer: "voie"
> >> > with 1 features and 14 fields
> >> > Feature type: wkbLineString with 2 dimensions
> >> >
> >> >> track.psp <- as(track, "psp")
> >> > Message d'avis :
> >> > In as.psp.SpatialLinesDataFrame(from) : 13 columns of data frame
> >> discarded
> >> >
> >> >> plot(track.psp)
> >> > Erreur dans image.default(c(893999.767449278, 895777.422954333),
> c(Inf,
> >> -Inf
> >> > :
> >> > 'x' and 'y' values must be finite and non-missing
> >> >
> >> > #plot(track) is OK
> >> >
> >> >> pts <- pointsOnLines(track.psp, eps=50)
> >> > Erreur dans ppp(x = x, y = y, window = win) :
> >> > all coordinate values are NA or NaN
> >> > ---
> >> >
> >> > Any help would be appreciated.
> >> >
> >> > The related SpatialLinesDataFrame track object is attached to this
> mail
> >> if
> >> > you'd like to have a look..
> >> >
> >> > Thanks!
> >> >
> >> > _______________________________________________
> >> > R-sig-Geo mailing list
> >> > R-sig-Geo@r-project.org
> >> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Michael Sumner
> >> Institute for Marine and Antarctic Studies, University of Tasmania
> >> Hobart, Australia
> >> e-mail: mdsumner@gmail.com
> >>
> >
> >        [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > R-sig-Geo@r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >
>
>
>
> --
> Michael Sumner
> Institute for Marine and Antarctic Studies, University of Tasmania
> Hobart, Australia
> e-mail: mdsumner@gmail.com
>

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