Rhelp wanted wrote:
Dear All I hope that someone can help.
I am working with sp pakage and akima
library("akima")
library(sp)
imagine lots of different dataframes, of row = 100 columns = 3 of x and y
coordinates with z values I will call these data frames for the sake of this
example akima
akima<-as.list(1:100)
producing 100 dataframes dataframes of the form akima[[i]]
I then wish to interp this list of coordinates:
akima.li<-as.list(1:100)
for (i in 1:100) akima.li[[i]]<-interp(akima[[i]]$x, akima[[i]]$y, akima
[[i]]$z)
so now I have 100 akima.li which I then transform into a dataframe of the
akima.li values
y<-as.list(1:100)
x<-as.list(1:100)
z<-as.list(1:100)
for (i in 1:endofrun){
y[[i]]= rep(akima.li[[i]]$x, each = length(akima.li[[i]]$y))
x[[i]] = rep(akima.li[[i]]$y, length(akima.li[[i]]$x))
z[[i]] = as.numeric(akima.li[[i]]$z)
}
abc<-as.list(1:100)
for (i in 1:endofrun){
abc[[i]]<- data.frame(x[[i]], y[[i]], z[[i]])
abc[[i]][is.na(abc[[i]])] <- 0}
so now I have 100 dataframes with x and y columns and corresponding z values
and any NAs are now 0.
This is where my problem starts I wish to use sp to state which columns are
coordinates of the form
for (i in 1:100) coordinates(abc[[i]])= ~x+y
and that all of the dataframes are a grid, such that.
for (i in 1:100) gridded(abc[[i]]) = TRUE
however I get error messeges such as:
Error in function (classes, fdef, mtable) : unable to find an inherited
method for function "coordinates<-", for signature "integer"
the input to coordinates should be a data.frame, which abc[[i]]
obviously isn't. Look at the meuse dataset from the sp-package for a
sample of how such a data.frame should look like.
cheers,
Paul
ps The r-sig-geo mailing list would be a better place to ask this question
and I do not know what this means.
I will then want to then go on to overlay such:
datapoint = data.frame(x = 10, y = 20)
coordinates(datapoint) = ~x+y
gridded(datapoint)=TRUE
value<-as.list(1:100)
for (i in 1:100) value [[i]]= abc[[...@data[overlay(abc[[i]], datapoint),]
then I will have a list of 100 "value" for each original dataframe
I would be appreciative if someone could tell me how I can allocate
coordinate and grided systems to an dataframes which are as.list.
I hope that is comprehendable and someone can help. I am very stuck
many thanks Sylvestre
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--
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone: +3130 274 3113 Mon-Tue
Phone: +3130 253 5773 Wed-Fri
http://intamap.geo.uu.nl/~paul
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