[R-sig-Geo] create data frame after spDists (re-posted)

[Swagath Navin]

Hello all,

Thank you very much for your reply.


Cheers,
Navin

On 8/25/12 10:02 AM, O'Hanlon, Simon J wrote:
> Hi Navin,
> As Rolf said spatstat does what you need, but I think for your application nncross() would be most suitable:
>
>> I am interested in finding met stations closer to the sample stations and creating a separate data frame with sample>locations and the nearest met station
>
> df1<-data.frame(x=seq(5.1,5.5, 0.1), y=seq(51,55,1))
> df2<-data.frame(x=seq(5,5.3, 0.1), y=seq(50,53,1))
>
> sample<- ppp( df1$x , y = df1$y , xrange = range(df1$x) , yrange = range( df1$y) )
>
> met<- ppp( df2$x , y = df2$y , xrange = range(df2$x) , yrange = range( df2$y ) )
>
> nncross( sample , met )
>
>            dist which
> 1 0.000000e+00     2
> 2 8.881784e-16     3
> 3 0.000000e+00     4
> 4 1.004988e+00     4
> 5 2.009975e+00     4
>
>
> HTH,
>
> Simon
> ________________________________________
> From: r-sig-geo-bounces at r-project.org [r-sig-geo-bounces at r-project.org] on behalf of Rolf Turner [r.turner at auckland.ac.nz]
> Sent: 24 August 2012 21:42
> To: swagath navin
> Cc: r-sig-geo at r-project.org
> Subject: Re: [R-sig-Geo] create data frame after spDists (re-posted)
>
> I believe that you would find the tools in the "spatstat" package
> (e.g. crossdist()) useful.
>
>       cheers,
>
>           Rolf Turner
>
> On 25/08/12 00:24, swagath navin wrote:
>> Hello all, sorry for re-posting, but i got a scrub message for my first mail.
>>
>> I have two spatial points data frame df1 showing sample locations and df2
>> meteorological stations. I am interested in finding met stations closer to
>> the sample stations and creating a separate data frame with sample
>> locations and the nearest met station.
>>
>> I calculated the distances between the stations:
>>
>> library(sp)
>>
>> df1<-data.frame(x=seq(5.1,5.5, 0.1), y=seq(51,55,1))
>> df2<-data.frame(x=seq(5,5.3, 0.1), y=seq(50,53,1))
>>
>> coordinates(df1)=~ x + y
>> coordinates(df2)=~ x + y
>>
>> dist=spDists(df1, df2, longlat = FALSE)
>>
>> but  how can i create a data frame with sample locations and nearest met
>> station as shown below:
>>
>> Sample location | Nearest Met station
>>
>> (5.1, 51)             | (5.1,51)
>>
>> for small number of stations i can do manually, but i have around 400
>> sample locations and 100 met stations.
>>
>> Thanks a lot for your time.
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