Type Members

1.  class ShardingKeyIndex[K] extends KeyIndex[K]

   An example of a generic KeyIndex which accounts for sharding that could occur in a data store like Apache Accumulo.

   An example of a generic KeyIndex which accounts for sharding that could occur in a data store like Apache Accumulo. Given a shard count (pre-configured), this index adds a "shard prefix" to the true index as given by the inner argument. Accumulo can shard based off of the first digit of a row ID, and since we use a round-robin approach to generate prefixes, this distributes spatially close indices across different shards, and thus helps avoid hot spots.

   Assumptions

   • The given shard count will be between 1 and 8.
   • The inner index will produce a value less than 2^60 for any given key.
2.  class ShardingKeyIndexRegistrator extends KeyIndexRegistrator

   Register ShardingKeyIndex's Codecs with the central GeoTrellis KeyIndex JsonFormat registry.

   Register ShardingKeyIndex's Codecs with the central GeoTrellis KeyIndex JsonFormat registry.

   Q: Why do we need to do this?

   A: The KeyIndex trait is critical to Tile layer IO. However, it is always used generically, without any class depending on KeyIndex's subtypes directly. This is advantageous, as the user never needs to externally keep track of what index they ingested a layer with. They can read and update a layer with less of a mental burden. That said, inventing new KeyIndex subclasses becomes labourous. In this way, we (the GeoTrellis authors) have accepted the burden of complexity to the benefit of our users.

3.  case class VoxelKey(x: Int, y: Int, z: Int) extends Product with Serializable

   A three-dimensional spatial key.

   A three-dimensional spatial key. A voxel is the 3D equivalent of a pixel.

4.  class ZVoxelKeyIndex extends KeyIndex[VoxelKey]

   A KeyIndex based on VoxelKey.

5.  class ZVoxelKeyIndexRegistrator extends KeyIndexRegistrator

   Register these Json codecs with Geotrellis's central registrator.

   Register these Json codecs with Geotrellis's central registrator. For more information on why this is necessary, see ShardingKeyIndex.scala.