| shp2SLDF {sp} | R Documentation |
These functions show how to build converters from external formats to build SpatialLinesDataFrame objects: shp2SLDF from "arc" type ESRI shapefiles read into "Map" objects using the read.shape() function in the maptools package; arcobj2SLDF from the list returned by the get.arcdata function in the RArcInfo package; and contourLines2SLDF from the list returned by the contourLines function in the graphics package (here the data frame is just the contour levels, with one Lines object made up of at least one Line object per level). In addition, Mapgen2SL reads a file in "Mapgen" format into a SpatialLines object.
shp2SLDF(shp, proj4string = CRS(as.character(NA)), IDs) arcobj2SLDF(arc, proj4string=CRS(as.character(NA)), IDs) contourLines2SLDF(cL, proj4string=CRS(as.character(NA))) Mapgen2SL(file, proj4string=CRS(as.character(NA)))
shp |
a "Map" object returned by the read.shape() function in the maptools package |
arc |
a list returned by the get.arcdata function in the RArcInfo package |
cL |
a list returned by the contourLines function in the graphics package |
proj4string |
Object of class "CRS"; see CRS-class |
IDs |
vector of unique character identifiers; if not given, suitable defaults will be used, and the same values inserted as data slot row names |
file |
filename of |
A SpatialLinesDataFrame object
Coastlines of varying resolution may be chosen online and downloaded in "Mapgen" text format from http://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html, but please note the 500,000 point limit on downloads, which is easy to exceed.
Roger Bivand; Edzer Pebesma
data(lnsshp) # retrieved as:
# library(maptools)
# lns <- read.shape(system.file("shapes/fylk-val.shp", package="maptools")[1])
res <- shp2SLDF(lns)
plot(res)
invisible(title(""))
data(co37_d90_arc) # retrieved as:
# library(RArcInfo)
# fl <- "http://www.census.gov/geo/cob/bdy/co/co90e00/co37_d90_e00.zip"
# download.file(fl, "co37_d90_e00.zip")
# e00 <- zip.file.extract("co37_d90.e00", "co37_d90_e00.zip")
# e00toavc(e00, "ncar")
# arc <- get.arcdata(".", "ncar")
res <- arcobj2SLDF(arc)
plot(res)
invisible(title(""))
res <- contourLines2SLDF(contourLines(volcano))
plot(res, col=terrain.colors(nrow(res@data)))
invisible(title(""))