Is it possible to overlay SpatialLinesDataFrame and SpatialPolygonDataFrame
I'm wondering if it's possible to do this R.
I have one information as SpatialLinesDataFrame and the other as spatialPolygonDataFrame. Is it possible to overlay these two data?
When I try to overlay them I get the following error:
jd <- overlay(res,hello)
Error in function (classes, fdef, mtable) : unable to find an inherited method for function
‘overlay’ for signature ‘"SpatialLinesDataFrame", "SpatialPolygonsDataFrame"’
In the above code, res is SpatialLinesDataFrame and hello is SpatialPolygonDataFrame.
I have a shapefile and then I have data points with x, y and z coordinates. I want to show contour lines in a shapefile.
The procedure I used is using the akima package for interpolation. the code i used for interpolation is
fld <- interp(x,y,z)
Then I changed it to a feature using the following code:
res <-ContourLines2SLDF(contourLines(fld))
The above command will save the contour lines as spatial data.
Then I read the shapefile and I draw both the shapefile and res like this:
p1 <-
spplot(hello,sp.layout=list(list("sp.lines",res)),col="blue",lwd=0,fill="grey",colorkey=F)
p1
"hello" is my shapefile, and "res" is the object I created as shown above.
The problem is that the outline stored in "res" is outside the shape file. So I want to copy this path from the shapefile and only display the path in the shapefile area.
So, I'm looking for a way to copy the outline layer with a polygonal layer.
I have attached the image I received with my code.
In the image you can see the lines from the shapefile. I also want to know how I can display the contour levels on the map.
Thank you very much.
Jdbaba
I also want to know what the overlay does. Does it cross the data area?
Thank.
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It looks like you are trying to anchor your lines in the polygon area. Use gIntersection
from package rgeos
. Here's a reproducible example:
library(rgeos)
xx <- SpatialPoints(coords=matrix(data=c(0,0), nrow=1))
xx <- gBuffer(spgeom=xx, width=1)
yy <- SpatialLines(list(Lines(Line(matrix(c(-1,1,-1,1), nrow=2)), ID=1)))
zz <- gIntersection(yy, xx)
You can overlay the plot like so:
plot(xx)
plot(zz, add = TRUE, col = "blue")
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Noah's answer worked pretty well for me. However, the output of his response is a SpatialLines object that cannot be saved as a shape file.
My two cents here on how you can convert your SpatialLines object to SpatialLinesDataFrame and save it as a shape file.
res.df <- fortify(res) # create data frame of res, your original SpatialLinesDataFrame
data <- data.frame(id = unique(res.df$id)) # get ids of road segments
rownames(data) <- data$id
# transform SpatialLines object into SpatialLinesDataFrame
zzSpatialLineDF <- SpatialLinesDataFrame(zz, data) # convert zz object keeping road ids
# 5 Save Shape File to your working directory
writeOGR(zzSpatialLineDF, dsn = '.', layer ='zzSpatialLineDF', driver = 'ESRI Shapefile')
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