mvt

README

mvt

Draw Mapbox Vector Tiles with ease.

Features

• Mapbox Vector Tiles 2.1 support
• MoveTo, LineTo, CubicTo, QuadraticTo
• Defined 256x256 canvas
• Uses floating points
• Add tags and IDs to features
• Fast encoding to MVT protobufs
• No external dependencies

Install

go get -u github.com/tidwall/mvt

Example

var tile mvt.Tile
l := tile.AddLayer("triforce")
f := l.AddFeature(mvt.Polygon)

f.MoveTo(128, 96)
f.LineTo(148, 128)
f.LineTo(108, 128)
f.LineTo(128, 96)
f.ClosePath()

f.MoveTo(148, 128)
f.LineTo(168, 160)
f.LineTo(128, 160)
f.LineTo(148, 128)
f.ClosePath()

f.MoveTo(108, 128)
f.LineTo(128, 160)
f.LineTo(88, 160)
f.LineTo(108, 128)
f.ClosePath()

data := tile.Render()

// Data now contains a valid mapbox vector tile protobuf 
// for sending over the internets and styling to your 
// heart's content.

Helper functions

• mvt.LatLonXY: Converts a lat/lon to the pixel offset for a specific tile.
• mvt.TileBounds: Returns the lat/lon boundary for a tile.

Contact

Josh Baker @tidwall

License

mvt source code is available under the MIT License.

Documentation

Index

• func LatLonXY(lat, lon float64, tileX, tileY, tileZ int) (x, y float64)
• func TileBounds(tileX, tileY, tileZ int) (minLat, minLon, maxLat, maxLon float64)
• type Feature
  • func (f *Feature) AddTag(key string, value interface{})
  • func (f *Feature) ClosePath()
  • func (f *Feature) CubicTo(x1, y1, x2, y2, x3, y3 float64)
  • func (f *Feature) LineTo(x, y float64)
  • func (f *Feature) MoveTo(x, y float64)
  • func (f *Feature) QuadraticTo(x1, y1, x2, y2 float64)
  • func (f *Feature) SetID(id uint64)
• type GeometryType
• type Layer
  • func (l *Layer) AddFeature(geomType GeometryType) *Feature
  • func (l *Layer) SetExtent(extent uint32)
• type Tile
  • func (t *Tile) AddLayer(name string) *Layer
  • func (t *Tile) Render() []byte

Functions

func LatLonXY

func LatLonXY(lat, lon float64, tileX, tileY, tileZ int) (x, y float64)

LatLonXY converts a lat/lon to an point x/y for the specified map tile.

func TileBounds

func TileBounds(tileX, tileY, tileZ int,
) (minLat, minLon, maxLat, maxLon float64)

TileBounds returns the lat/lon bounds around a tile.

Types

type Feature

type Feature struct {
	// contains filtered or unexported fields
}

Feature represents a feature

func (*Feature) AddTag

func (f *Feature) AddTag(key string, value interface{})

AddTag adds a tag

func (*Feature) ClosePath

func (f *Feature) ClosePath()

ClosePath closes a path

func (*Feature) CubicTo

func (f *Feature) CubicTo(x1, y1, x2, y2, x3, y3 float64)

CubicTo draw a cubic curve

func (*Feature) LineTo

func (f *Feature) LineTo(x, y float64)

LineTo draws a line to a point. The tile is 256x256.

func (*Feature) MoveTo

func (f *Feature) MoveTo(x, y float64)

MoveTo move to a point. The tile is 256x256.

func (*Feature) QuadraticTo

func (f *Feature) QuadraticTo(x1, y1, x2, y2 float64)

QuadraticTo draw a quadratic curve

func (*Feature) SetID

func (f *Feature) SetID(id uint64)

SetID set the id

type GeometryType

type GeometryType byte

GeometryType represents geometry type

const (
	// Unknown is an unknown geometry type
	Unknown GeometryType = 0
	// Point is a point
	Point GeometryType = 1
	// LineString is a line string
	LineString GeometryType = 2
	// Polygon is a polygon
	Polygon GeometryType = 3
)

type Layer

type Layer struct {
	// contains filtered or unexported fields
}

Layer represents a layer

func (*Layer) AddFeature

func (l *Layer) AddFeature(geomType GeometryType) *Feature

AddFeature add a geometry feature

func (*Layer) SetExtent

func (l *Layer) SetExtent(extent uint32)

SetExtent sets the layers extent. Default is 4096.

type Tile

type Tile struct {
	// contains filtered or unexported fields
}

Tile represents a Mapbox Vector Tile

func (*Tile) AddLayer

func (t *Tile) AddLayer(name string) *Layer

AddLayer adds a layer

func (*Tile) Render

func (t *Tile) Render() []byte

Render renders the tile to a protobuf file for displaying on a map.