readWKB {wkb}

Convert WKB to Spatial Objects

Description

Converts well-known binary (WKB) geometry representations to Spatial objects.

Usage

readWKB(wkb, id = NULL, proj4string = CRS(as.character(NA)))

Arguments

wkb

list in which each element is a raw vector consisting of a WKB geometry representation.

id

character vector of unique identifiers of geometries. The length of id must be the same as the length of the wkb list.

proj4string

projection string of class CRS.

Details

Supported WKB geometry types are Point, LineString, Polygon, MultiPoint, MultiLineString, and MultiPolygon. All elements in the list must have the same WKB geometry type. The WKB geometry representations may use little-endian or big-endian byte order.

The argument wkb may also be a raw vector consisting of one WKB geometry representation. In that case, the argument id must have length one.

Value

An object inheriting class Spatial.

The return value may be an object of class SpatialPoints, SpatialLines, SpatialPolygons, or a list in which each element is an object of class SpatialPoints. The class of the return value depends on the WKB geometry type as shown in the table below.

Type of WKB geometry	Class of return value
Point	SpatialPoints
LineString	SpatialLines
Polygon	SpatialPolygons
MultiPoint	list of SpatialPoints
MultiLineString	SpatialLines
MultiPolygon	SpatialPolygons

See Also

writeWKB, hex2raw

Examples

# create a list of WKB geometry representations of type Point
wkb <- list(
  as.raw(c(0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
           0xf0, 0x3f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x40)),
  as.raw(c(0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
           0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40))
)

# convert to object of class SpatialPoints
obj <- readWKB(wkb)


# create a list of WKB geometry representations of type MultiPoint
wkb <- list(
  as.raw(c(0x01, 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x01,
           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x3f,
           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x40)),
  as.raw(c(0x01, 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x01,
           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40,
           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40)))

# convert to list of objects of class SpatialPoints
obj <- readWKB(wkb)


# create a list of WKB geometry representations of type MultiLineString
wkb <- list(
  as.raw(c(0x01, 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x02,
           0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
           0x00, 0x00, 0xf0, 0x3f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08,
           0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00,
           0x00, 0x00, 0x00, 0x00, 0x00, 0x40)),
  as.raw(c(0x01, 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x02,
           0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
           0x00, 0x00, 0xf0, 0x3f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0,
           0x3f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00,
           0x00, 0x00, 0x00, 0x00, 0xf8, 0x3f)))

# convert to object of class SpatialLines
obj <- readWKB(wkb)


# create a list of WKB geometry representations of type Polygon
wkb <- list(
  as.raw(c(0x01, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x05, 0x00,
           0x00, 0x00, 0x34, 0x03, 0xf0, 0xac, 0xce, 0x66, 0x5d, 0xc0, 0x8f,
           0x27, 0x95, 0x21, 0xab, 0xa6, 0x44, 0x40, 0xa0, 0x32, 0x81, 0x18,
           0x78, 0x83, 0x5d, 0xc0, 0xc8, 0xd2, 0xa0, 0xee, 0x23, 0x0b, 0x41,
           0x40, 0x80, 0xec, 0x72, 0x54, 0xde, 0xb1, 0x5f, 0xc0, 0xc8, 0xd2,
           0xa0, 0xee, 0x23, 0x0b, 0x41, 0x40, 0xec, 0x1b, 0x04, 0xc0, 0x87,
           0xce, 0x5f, 0xc0, 0x8f, 0x27, 0x95, 0x21, 0xab, 0xa6, 0x44, 0x40,
           0x34, 0x03, 0xf0, 0xac, 0xce, 0x66, 0x5d, 0xc0, 0x8f, 0x27, 0x95,
           0x21, 0xab, 0xa6, 0x44, 0x40)),
  as.raw(c(0x01, 0x03, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x05, 0x00,
           0x00, 0x00, 0x08, 0x36, 0xdc, 0x8b, 0x9f, 0x3d, 0x51, 0xc0, 0x0f,
           0xb3, 0x2a, 0x6a, 0x3f, 0x1c, 0x46, 0x40, 0x47, 0xcb, 0x54, 0xe7,
           0xcb, 0x5e, 0x51, 0xc0, 0x45, 0x81, 0x50, 0x31, 0xfa, 0x80, 0x42,
           0x40, 0xa9, 0xba, 0x74, 0x6d, 0xf5, 0xa1, 0x53, 0xc0, 0x45, 0x81,
           0x50, 0x31, 0xfa, 0x80, 0x42, 0x40, 0xe8, 0x4f, 0xed, 0xc8, 0x21,
           0xc3, 0x53, 0xc0, 0x0f, 0xb3, 0x2a, 0x6a, 0x3f, 0x1c, 0x46, 0x40,
           0x08, 0x36, 0xdc, 0x8b, 0x9f, 0x3d, 0x51, 0xc0, 0x0f, 0xb3, 0x2a,
           0x6a, 0x3f, 0x1c, 0x46, 0x40)))

# convert to object of class SpatialPolygons
obj <- readWKB(wkb)


# specify id and proj4string
obj <- readWKB(
  wkb,
  id = c("San Francisco", "New York"),
  proj4string = sp::CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs")
)