Charger

A marauder's charged collection of Vector Tile Tools

The Encoder is the main module to work with vector tiles. When talking about vector tiles, it refers to a standard developed by MapBox (https://github.com/mapbox/vector-tile-spec).

Detailed documentation of the Marauder components coming soon on our webpage https://marauder.io.

The collection consists of following charged components:

Encoder
Clipper
Models
Projector
Utils

Encoder

A Encoder and Decoder for Mapbox Vector Tiles. We implement the specification version 2.1 (https://github.com/mapbox/vector-tile-spec/tree/master/2.1).

Features

Fast vector tile encoding from simple GeoJSON like Objects
Fast Vector tile decoding
Efficient & flexible vector tile merging
- Directly from two BLOBs
- By injecting one tile in another's encoding function call
Runs without JTS or GeoTools dependencies
- Also JTS Geometry support is implemented
Allows to merge tiles without completely decoding them

Usage

Gradle

Artifacts are published on OSS Sonatype and Maven Central.

Gradle dependency:

compile group: 'io.marauder.supercharger', name: 'encoder', version: '0.0.3'
compile group: 'io.marauder.supercharger', name: 'models', version: '0.0.3'
compile group: 'io.marauder.supercharger', name: 'projector', version: '0.0.3'
compile group: 'io.marauder.supercharger', name: 'utils', version: '0.0.3'
compile group: 'io.marauder.supercharger', name: 'clipper', version: '0.0.3'

For snapshots use this repository:

maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }

Encoding Example

val f1 = Feature(
                type = GeoJsonType.Feature,
                geometry = Geometry.Polygon(
                        type = GeometryType.Polygon,
                        coordinates = listOf(
                                listOf(
                                        listOf(10.0, 10.0), listOf(10.0, 20.0), listOf(20.0, 20.0), listOf(20.0, 10.0), listOf(10.0, 10.0)
                                )
                        )
                ),
                properties = mapOf("A" to Value.StringValue("B"), "N" to Value.IntValue(3), "C" to Value.IntValue(2))
        )
val f1 = JSON.plain.parse<List<Feature>>(File("features.geojson").readText())
val encoder = Encoder()
val tile : vector_tile.VectorTile.Tile = encoder.encode(listOf(f1), "test1")
val tile : vector_tile.VectorTile.Tile = encoder.encode(listOf(f2), "test2")

Decoding Example

val bytes = File("file.pbf").readBytes()
val encoder = Encoder()
val features: List<Feature> = encoder.decode(bytes)

Current Limitations

Multiple layers are supported, but merging by injecting features into the encoding process does support only one layer.

Hints

As intended our Encoder/Decoder does no coordinate transformation and clipping

Geometry Clipping

Provides functionality to clip functions in x or y direction on given boundaries.

val clipper = Clipper()
clipper.clip(fc = featureCollection, ...)

Geometry Models

Available models

GeoJson - Feature collection
Feature - A features
Geometry - A geometry, sub classes used to instantiate
Value - Holds a feature's property value, sub classes used to instantiate

Geometry JTS/WKT support

val g1 = Geometry.fromJTS(jtsObject)
val g2 = Geometry.fromWKT(wktString)

val jts = g1.toJTS()
val wkt = g1.toWKT()

Geometry Projector

val projector = Projector(extend = 4096)
projector.transformGeometry(...)

Geometry Utils

Util functions for geometry intersection testing and geometry simplifications.

License

SuperCharger is licensed under the Apache License, Version 2.0.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

f7o/charger