wkb

Documentation

Overview

Package wkb 实现了 WKB 的编码和解码。

如果你想将 几何图形编码后以 WKB 存进 PostgreSQL/PostGIS。你必须设置 binary_parameters=yes，在 你向 sql.Open传递的数据资源中

Example (Scan)

type City struct {
	Name     string
	Location wkb.Point
}

db, mock, err := sqlmock.New()
if err != nil {
	log.Fatal(err)
}
defer db.Close()

mock.ExpectQuery(`SELECT name, ST_AsBinary\(location\) FROM cities WHERE name = \?;`).
	WithArgs("London").
	WillReturnRows(
		sqlmock.NewRows([]string{"name", "location"}).
			AddRow("London", geomtest.MustHexDecode("010100000052B81E85EB51C03F45F0BF95ECC04940")),
	)

var c City
if err := db.QueryRow(`SELECT name, ST_AsBinary(location) FROM cities WHERE name = ?;`, "London").Scan(&c.Name, &c.Location); err != nil {
	log.Fatal(err)
}

fmt.Printf("Longitude: %v\n", c.Location.X())
fmt.Printf("Latitude: %v\n", c.Location.Y())

Output:

Longitude: 0.1275
Latitude: 51.50722

Example (Value)

type City struct {
	Name     string
	Location wkb.Point
}

db, mock, err := sqlmock.New()
if err != nil {
	log.Fatal(err)
}
defer db.Close()

mock.ExpectExec(`INSERT INTO cities \(name, location\) VALUES \(\?, \?\);`).
	WithArgs("London", geomtest.MustHexDecode("010100000052B81E85EB51C03F45F0BF95ECC04940")).
	WillReturnResult(sqlmock.NewResult(1, 1))

c := City{
	Name:     "London",
	Location: wkb.Point{geom.NewPoint(geom.XY).MustSetCoords(geom.Coord{0.1275, 51.50722})},
}

result, err := db.Exec(`INSERT INTO cities (name, location) VALUES (?, ?);`, c.Name, &c.Location)
if err != nil {
	log.Fatal(err)
}
rowsAffected, _ := result.RowsAffected()
fmt.Printf("%d rows affected", rowsAffected)

Output:

1 rows affected

Index

• Variables
• func Marshal(g geom.T, byteOrder binary.ByteOrder) ([]byte, error)
• func Read(r io.Reader) (geom.T, error)
• func Unmarshal(data []byte) (geom.T, error)
• func Write(w io.Writer, byteOrder binary.ByteOrder, g geom.T) error
• type ErrExpectedByteSlice
  • func (e ErrExpectedByteSlice) Error() string
• type GeometryCollection
  • func (gc *GeometryCollection) Scan(src interface{}) error
  • func (gc *GeometryCollection) Value() (driver.Value, error)
• type LineString
  • func (ls *LineString) Scan(src interface{}) error
  • func (ls *LineString) Value() (driver.Value, error)
• type MultiLineString
  • func (mls *MultiLineString) Scan(src interface{}) error
  • func (mls *MultiLineString) Value() (driver.Value, error)
• type MultiPoint
  • func (mp *MultiPoint) Scan(src interface{}) error
  • func (mp *MultiPoint) Value() (driver.Value, error)
• type MultiPolygon
  • func (mp *MultiPolygon) Scan(src interface{}) error
  • func (mp *MultiPolygon) Value() (driver.Value, error)
• type Point
  • func (p *Point) Scan(src interface{}) error
  • func (p *Point) Value() (driver.Value, error)
• type Polygon
  • func (p *Polygon) Scan(src interface{}) error
  • func (p *Polygon) Value() (driver.Value, error)

Examples

• Package (Scan)
• Package (Value)

Variables

var (
	// XDR is big endian.
	XDR = wkbcommon.XDR
	// NDR is little endian.
	NDR = wkbcommon.NDR
)

Functions

func Marshal

func Marshal(g geom.T, byteOrder binary.ByteOrder) ([]byte, error)

Marshal函数 编码任意一个几何图形到 []byte中.

func Read

func Read(r io.Reader) (geom.T, error)

Read函数 从 r 中读取任意的几何图形.

func Unmarshal

func Unmarshal(data []byte) (geom.T, error)

Unmarshal函数 从一个 []byte 中解码任意几何图形。

func Write

func Write(w io.Writer, byteOrder binary.ByteOrder, g geom.T) error

Write函数 向 w 中写入任意一个几何图形.

Types

type ErrExpectedByteSlice

type ErrExpectedByteSlice struct {
	Value interface{}
}

ErrExpectedByteSlice函数 将返回当 需要一个 []byte时.

func (ErrExpectedByteSlice) Error

func (e ErrExpectedByteSlice) Error() string

type GeometryCollection

type GeometryCollection struct {
	*geom.GeometryCollection
}

A GeometryCollection 是一个WKB编码的 GeometryCollection,实现了 sql.Scanner和 driver.Valuer接口.

func (*GeometryCollection) Scan

func (gc *GeometryCollection) Scan(src interface{}) error

Scan scans from a []byte.

func (*GeometryCollection) Value

func (gc *GeometryCollection) Value() (driver.Value, error)

Value returns the WKB encoding of gc.

type LineString

type LineString struct {
	*geom.LineString
}

A LineString 是一个WKB编码的 LineString,实现了 sql.Scanner和 driver.Valuer接口.

func (*LineString) Scan

func (ls *LineString) Scan(src interface{}) error

Scan scans from a []byte.

func (*LineString) Value

func (ls *LineString) Value() (driver.Value, error)

Value returns the WKB encoding of ls.

type MultiLineString

type MultiLineString struct {
	*geom.MultiLineString
}

A MultiLineString 是一个WKB编码的 MultiLineString,实现了 sql.Scanner和 driver.Valuer接口.

func (*MultiLineString) Scan

func (mls *MultiLineString) Scan(src interface{}) error

Scan scans from a []byte.

func (*MultiLineString) Value

func (mls *MultiLineString) Value() (driver.Value, error)

Value returns the WKB encoding of mls.

type MultiPoint

type MultiPoint struct {
	*geom.MultiPoint
}

A MultiPoint 是一个WKB编码的 MultiPoint,实现了 sql.Scanner和 driver.Valuer接口.

func (*MultiPoint) Scan

func (mp *MultiPoint) Scan(src interface{}) error

Scan scans from a []byte.

func (*MultiPoint) Value

func (mp *MultiPoint) Value() (driver.Value, error)

Value returns the WKB encoding of mp.

type MultiPolygon

type MultiPolygon struct {
	*geom.MultiPolygon
}

A MultiPolygon 是一个WKB编码的 MultiPolygon,实现了 sql.Scanner和 driver.Valuer接口.

func (*MultiPolygon) Scan

func (mp *MultiPolygon) Scan(src interface{}) error

Scan scans from a []byte.

func (*MultiPolygon) Value

func (mp *MultiPolygon) Value() (driver.Value, error)

Value returns the WKB encoding of mp.

type Point

type Point struct {
	*geom.Point
}

A Point is 是一个WKB编码的 Point,实现了 sql.Scanner和 driver.Valuer接口.

func (*Point) Scan

func (p *Point) Scan(src interface{}) error

Scan方法 从 []byte 中扫描（遍历）.

func (*Point) Value

func (p *Point) Value() (driver.Value, error)

Value方法 返回 p对象的 WKB 编码

type Polygon

type Polygon struct {
	*geom.Polygon
}

A Polygon 是一个WKB编码的 Polygon,实现了 sql.Scanner和 driver.Valuer接口.

func (*Polygon) Scan

func (p *Polygon) Scan(src interface{}) error

Scan scans from a []byte.

func (*Polygon) Value

func (p *Polygon) Value() (driver.Value, error)

Value returns the WKB encoding of p.