scalagisgeotrellis

Dynamically determine aggregate KeyBounds in GeoTrellis

Given an RDD[(SpatialKey, Tile)] in GeoTrellis, how do I compute the aggregate KeyBounds[SpatialKey]?

Solution

  • For any RDD[(K, V])] where K is Boundable, i.e. there is an implicit Boundable[K] in scope, you can do:

    val bounds: KeyBounds[K] =
  tiles.map({ case (key, _) => KeyBounds(key, key) }).reduce(_ combine _)

    This will work over SpatialKey and SpaceTimeKey, as GeoTrellis provides the implicit Boundable typeclasses for those types. So in your case,

    val bounds: KeyBounds[SpatialKey] =
  tiles.map({ case (key, _) => KeyBounds(key, key) }).reduce(_ combine _)

    will work.