Hi Benjamin,
I don't know if you have read carefully the help on
SpatialPolygonsDataFrame but it is written about the "data" arugment :
"the number of rows in ‘data’ should equal the number of Polygons-class
objects in ‘Sr’"
In your example 'spPolys' correspond to 'Sr' and is a SpatialPolygons
which length is 1.
You should build a SpatialPolygons with length equal to the number of
rows of polyData.
The code below should help you :
xx <- mapply (
FUN=function(x, y) Polygons(list(x), y),
polyList, paste('FUBAR', 1:length(polyList), sep='.'),
SIMPLIFY=FALSE)
spPolys <- SpatialPolygons(xx)
polyData <- data.frame (test=1:length(spPolys)) # actually the datayou
want to use
dfReturn <- SpatialPolygonsDataFrame (spPolys, polyData, match.ID=FALSE)
Best,
Vlad
-------
Vladislav Navel
SCAN
www.scan-datamining.com
Le 07/03/2012 04:22, Benjamin Stewart a écrit :
I feel like I have done this before, so I am sorry if I have made a stupid
mistake, however, I am out of ideas.
I am trying to make a shapefile out of a list of polygons. I want to
include the a data frame as well, but I can't seem to create a
SpatialPolygons-Class longer than one object. The one object has all the
individual features when I map it, but it is only one object. Here is my
code:
xx = Polygons(polyList, "FUBAR")
spPolys = SpatialPolygons(list(xx))
polyData = (The data frame I want to use)
dfReturn = SpatialPolygonsDataFrame(spPolys, polyData, match.ID=F)
Any ideas? If I replace the polyData with data.frame(ID = 1) stupid thing
works!
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