contourLines2SLDF {sp}R Documentation

Converter functions to build SpatialLinesDataFrame objects

Description

These functions show how to build converters to SpatialLinesDataFrame objects: 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.

Usage

contourLines2SLDF(cL, proj4string=CRS(as.character(NA)))
Mapgen2SL(file, proj4string=CRS(as.character(NA)))

Arguments

cL a list returned by the contourLines function in the graphics package
proj4string Object of class "CRS"; see CRS-class
file filename of a file containing a Mapgen line data set

Value

A SpatialLinesDataFrame object

Note

Coastlines of varying resolution may be chosen online and downloaded in "Mapgen" text format from http://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html, most conveniently using the interactive selection tool, but please note the 500,000 point limit on downloads, which is easy to exceed.

Author(s)

Roger Bivand; Edzer Pebesma

See Also

SpatialLines-class

Examples

#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(""))

[Package sp version 0.8-3 Index]