VectorTiles

Invented by Mapbox, VectorTiles are a combination of the ideas of finite-sized tiles and vector geometries. Mapbox maintains the official implementation spec for VectorTile codecs. The specification is free and open source.

VectorTiles are advantageous over raster tiles in that:

• They are typically smaller to store
• They can be easily transformed (rotated, etc.) in real time
• They allow for continuous (as opposed to step-wise) zoom in Slippy Maps

Raw VectorTile data is stored in the protobuf format. Any codec implementing the spec must decode and encode data according to this .proto schema.

For more detailed information on VectorTiles, our data types, and usage instructions for this library, see the Scaladocs.

Updating scalapb

This codec uses ScalaPB to auto-generate its .pbf -> Scala bridge code. The tool itself offers an SBT plugin to do this, but I've found it easier to run their spbc tool directly.

Once you have that, generate the code as follows. From the vectortile/ directory:

spbc vector_tile.proto --scala_out=.

This will produce some scala sources that will need to override what's present in /vectortile/src/main/scala/geotrellis/vectortile/internal/vector_tile. This should be two files, Tile.scala and VectorTileProto.scala.

To get everything to compile, you will also have to manually change the package names in each of the files to:

package geotrellis.vectortile.internal.vector_tile

Please also add the Apache 2 license headers to each file.

You will have to complete this entire process whenever you choose to update the scalapb dependency line in vectortile/build.sbt.