Encoding Vector Tiles¶

VectorTileBuilder assembles a VectorTile from JTS Geometry instances; VectorTileCodec.encode(...) serializes the result to MVT bytes.

Build a tile¶

import io.tileverse.vectortile.model.VectorTile;
import io.tileverse.vectortile.mvt.VectorTileBuilder;
import io.tileverse.vectortile.mvt.VectorTileCodec;
import org.locationtech.jts.geom.Geometry;

VectorTileBuilder builder = new VectorTileBuilder();

builder.layer()
        .name("buildings")
        .feature()
            .id(123)
            .geometry(buildingPolygon)
            .attribute("height", 50)
            .attribute("type", "residential")
            .build()       // returns LayerBuilder
        .build();          // returns VectorTileBuilder

VectorTile tile = builder.build();

LayerBuilder.feature() opens a FeatureBuilder; chain .id(...) / .geometry(...) / .attribute(...) / .attributes(Map) then call .build() to attach the feature to its layer and return the LayerBuilder for the next feature.

Shorthand for many features¶

When you have a stream of (properties, geometry) pairs (e.g. iterating a SimpleFeatureCollection), the LayerBuilder.feature(Map, Geometry [, long id]) overloads skip the inner builder:

features.forEach(simpleFeature ->
        roadsLayer.feature(simpleFeature.getProperties(), simpleFeature.getGeometry()));

Encode to bytes¶

Three target shapes:

VectorTileCodec codec = new VectorTileCodec();

byte[] bytes = codec.encode(tile);                       // heap byte[]
codec.encode(tile, OutputStream sink);                   // streaming
codec.encode(tile, ByteBuffer sink);                     // pre-sized buffer

The OutputStream overload is the right choice when you're piping straight to an HTTP response or writing into a PMTiles writer's tile slot: no intermediate heap copy.

Configure encoding¶

VectorTileBuilder has tile-wide knobs that take effect at build() time:

builder
    .setExtent(4096)                          // tile coordinate extent (default 4096)
    .setClipBuffer(64)                        // pixels of buffer around the tile bbox
    .setAutoIncrementIds(true)                // assign ids automatically when features omit them
    .setSimplificationDistanceTolerance(1.0)  // Douglas-Peucker tolerance in tile units
    .setUsePrecisionModelSnapping(true);      // snap to integer coordinates before encoding

These are tile-wide, not per-layer. Tune them once for the output dataset.

Coordinates and units¶

The geometries you pass to the builder must already be in tile coordinates: origin at the tile's top-left, y growing downward, extent given by setExtent(...) (typically 4096). If your source is in a CRS (EPSG:3857, etc.), project to tile coordinates first using the matching TileMatrixSet. See Tile Matrix Set.