spEasy: Create SpatialLines* or SpatialPolygons*

In raster: Geographic Data Analysis and Modeling

Description

Helper functions to simplify the creation of SpatialLines* or SpatialPolygons* objects from coordinates.

Usage

spLines(x, ..., attr=NULL, crs="") 
spPolygons(x, ..., attr=NULL, crs="") 

Arguments

x	matrix of list with matrices. Each matrix must have two columns with x and y coordinates (or longitude and latitude, in that order). Multi-line or multi-polygon objects can be formed by combining matrices in a list
...	additional matrices and/or lists with matrices
attr	data.frame with the attributes to create a *DataFrame object. The number of rows must match the number of lines/polgyons
crs	the coordinate reference system (PROJ4 or WKT notation)

Value

SpatialLines* or SpatialPolygons*

Examples

x1 <- rbind(c(-180,-20), c(-140,55), c(10, 0), c(-140,-60))
x2 <- rbind(c(-10,0), c(140,60), c(160,0), c(140,-55))
x3 <- rbind(c(-125,0), c(0,60), c(40,5), c(15,-45))
x4 <- rbind(c(41,-41.5), c(51,-35), c(62,-41), c(51,-50))

a <- spLines(x1, x2, x3)
b <- spLines(x1, list(x2, x3), attr=data.frame(id=1:2), crs='+proj=longlat +datum=WGS84')
b

hole <- rbind(c(-150,-20), c(-100,-10), c(-110,20), c(-130,10))
d <- spPolygons(list(x1,hole), x2, list(x3, x4))

att <- data.frame(ID=1:3, name=c('a', 'b', 'c'))
e <- spPolygons(list(x1,hole), x2, list(x3, x4), attr=att, crs='+proj=longlat +datum=WGS84')
e

Example output

Loading required package: sp
class       : SpatialLinesDataFrame 
features    : 2 
extent      : -180, 160, -60, 60  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 
variables   : 1
names       : id 
min values  :  1 
max values  :  2 
class       : SpatialPolygonsDataFrame 
features    : 3 
extent      : -180, 160, -60, 60  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +datum=WGS84 
variables   : 2
names       : ID, name 
min values  :  1,    a 
max values  :  3,    c 

raster documentation built on Jan. 5, 2021, 3:01 a.m.