Dear colleague, dear ADE users.
As pointed out by Prof Komomen, the intertype function in ADS in ADE, that
characterises the relative spatial structure of two populations, gives
warnings when some points have the same co-ordinates, either within one
population, or from the two populations.
The fact that 2 points have the same co-ordinates is clearly not a problem :
it can be encountered in many real data sets, especially depending on the
measuring precision. There is no problem in the computation of the intertype
function, each point being considered as a neighbour of the other for any
distance.
I have checked the program source, and I can confirm that the K12-function
handles data with such points having the same co-ordinates and that the
results are reliable.
The warning given in such cases is not intended to point out an error, but
only to give users a possibility to detect eventual mistakes in the data.
Indeed, mistakes during the creation of the data file can sometime result in
such "double" points, that are difficult to detect in big data files.
I hope this answers to the question.
Sincerely yours,
-------------------------------------------------------
François Goreaud
CEMAGREF, LISC
24 avenue des Landais - BP 50085
63172 AUBIERE CEDEX 1 - France
Tel. : 33 (0)4.73.44.06.80
Fax : 33 (0)4.73.44.06.96
email : francois.goreaud@clermont.cemagref.fr
-------------------------------------------------------
> -- Message Original --
> De: Atte Komonen <komonen@joyx.joensuu.fi>
> À: Raphael.Pelissier@mpl.ird.fr
> Envoyé le: 22-09-2003
> Sujet: question about ADE
>
>
>
> Dear Daniel Chessel,
>
> I find the ADE-software very interesting and useful. I have one question
> about
> the intertype K12-function, especially about the population independence
> hypothesis.
>
> My data includes some coordinates that are shared between two species and
> ADE
> gives a warning about this. Can the K12-function handle data with shared
> coordinates or are the results unreliable?
>
> Sincerely Yours, Atte Komonen
>
>
> --
> Senior Lecturer
> Coordinator of Environmental Sciences
> Faculty of Forest Sciences
> University of Joensuu
> P.O. Box 111
> FIN-80101 Joensuu
> FINLAND
>
> Tel. +358-(0)13-251 4091
> Fax. +358-(0)13-251 4444
> atte.komonen@joensuu.fi
> http://www.joensuu.fi/forestcentre/
>
>
>
>
>
>
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