[R] spatstat error

[Rolf Turner]

Questions about spatstat should be directed to the R-Sig-Geo list, or
better still, to the package maintainers.

To add a bit to what Blaser Nello has already told you:

(1) Your syntax in respect of the use of the min() function is indeed
incomprehensibly bizarre.

(2) Blaser Nello has indicated useful *correct* alternatives. Another
possibility is to use the ripras() function from spatstat, e.g.

Dantos <- with(Datos,ppp(x,y,window=ripras(x,y,shape="rectangle")))

(3) If you are actually going to do any statistical analysis of the 
point pattern
then it is a VERY BAD idea to "estimate" the observation window from the
data. The observation window should be *known* a priori, else the 
statistical
results can be wrong or misleading. To quote from Adrian Baddeley's notes:

> It is important to know the window W, since we need to know where 
> points were not
> observed. Even something as simple as estimating the density of points 
> depends on the
> window. It would be wrong, or at least different, to analyze a point 
> pattern dataset by
> “guessing” the appropriate window. An analogy may be drawn with the 
> difference between
> sequential experiments and experiments in which the sample size is 
> fixed a priori.

See:
> @techreport{Baddeley2010,
> author = {Adrian Baddeley},
> title = {Analysing spatial point patterns in \textsf{R},
> \textbf{Version 4.1}},
> institution = {CSIRO},
> year = {2010},
> month = {December},
> note = {URL: 
> \url{http://www.csiro.au/resources/Spatial-Point-Patterns-in-R}},
> type = {Workshop Notes}
> }

cheers,

Rolf Turner

On 03/22/2013 12:19 PM, papao wrote:
> Good day
>
>   
>
> Im working with some coordinates, and want to create a PPP object, I found
> that error:
>
>   
>
>> Datos=read.table("puntos_texto.txt",dec=".",sep="\t",header=T)
>> summary(Datos)
>         id               y                 x
>
>   Min.   :   1.0   Min.   :1013581   Min.   :1177842
>
>   1st Qu.: 821.2   1st Qu.:1014442   1st Qu.:1179658
>
>   Median :1641.5   Median :1014455   Median :1179670
>
>   Mean   :1641.8   Mean   :1014465   Mean   :1179652
>
>   3rd Qu.:2462.8   3rd Qu.:1014473   3rd Qu.:1179680
>
>   Max.   :3283.0   Max.   :1015575   Max.   :1180213
>
>   
>
> danta=ppp(Datos$x,Datos$y,c(min(Datos$x)1177842,max(Datos$x)1180213),c(min(D
> atos$y)1013581,max(Datos$y)1015575))
>
> Error: inesperado constante numérica en
> "danta=ppp(Datos$x,Datos$y,c(min(Datos$x)1177842"
>
>   
>
> danta=ppp(Datos$x,Datos$y,c(min(Datos$x)"1177842",max(Datos$x)"1180213"),c(m
> in(Datos$y)"1013581",max(Datos$y)"1015575"))
>
> Error: inesperado string constante en
> "danta=ppp(Datos$x,Datos$y,c(min(Datos$x)"1177842""
>
> danta=ppp(Datos$x,Datos$y,window=owin(c(min(Datos$x)"1177842",max(Datos$x)"1
> 180213"),c(min(Datos$y)"1013581",max(Datos$y)"1015575")))
>
> Error: inesperado string constante en
> "danta=ppp(Datos$x,Datos$y,window=owin(c(min(Datos$x)"1177842""
>