geotrellis.spark.mapalgebra.focal.FocalOperation.scala Maven / Gradle / Ivy

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GeoTrellis is an open source geographic data processing engine for high performance applications.

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package geotrellis.spark.mapalgebra.focal

import geotrellis.spark._
import geotrellis.spark.buffer._
import geotrellis.raster._
import geotrellis.raster.mapalgebra.focal._
import geotrellis.vector._
import geotrellis.util.MethodExtensions

import org.apache.spark.rdd.RDD
import org.apache.spark.SparkContext._

import spire.syntax.cfor._

import annotation.tailrec
import scala.reflect.ClassTag
import scala.collection.mutable.ArrayBuffer


object FocalOperation {
  private def mapOverBufferedTiles[K: SpatialComponent: ClassTag](bufferedTiles: RDD[(K, BufferedTile[Tile])], neighborhood: Neighborhood)
      (calc: (Tile, Option[GridBounds]) => Tile): RDD[(K, Tile)] =
    bufferedTiles
      .mapValues { case BufferedTile(tile, gridBounds) => calc(tile, Some(gridBounds)) }

  def apply[K: SpatialComponent: ClassTag](rdd: RDD[(K, Tile)], neighborhood: Neighborhood)
      (calc: (Tile, Option[GridBounds]) => Tile)(implicit d: DummyImplicit): RDD[(K, Tile)] =
    mapOverBufferedTiles(rdd.bufferTiles(neighborhood.extent), neighborhood)(calc)

  def apply[K: SpatialComponent: ClassTag](rdd: RDD[(K, Tile)], neighborhood: Neighborhood, layerBounds: GridBounds)
      (calc: (Tile, Option[GridBounds]) => Tile): RDD[(K, Tile)] =
    mapOverBufferedTiles(rdd.bufferTiles(neighborhood.extent, layerBounds), neighborhood)(calc)

  def apply[K: SpatialComponent: ClassTag](rasterRDD: TileLayerRDD[K], neighborhood: Neighborhood)
      (calc: (Tile, Option[GridBounds]) => Tile): TileLayerRDD[K] =
    rasterRDD.withContext { rdd =>
      apply(rdd, neighborhood, rasterRDD.metadata.gridBounds)(calc)
    }
}

abstract class FocalOperation[K: SpatialComponent: ClassTag] extends MethodExtensions[TileLayerRDD[K]] {

  def focal(n: Neighborhood)
      (calc: (Tile, Option[GridBounds]) => Tile): TileLayerRDD[K] =
    FocalOperation(self, n)(calc)

  def focalWithCellSize(n: Neighborhood)
      (calc: (Tile, Option[GridBounds], CellSize) => Tile): TileLayerRDD[K] = {
    val cellSize = self.metadata.layout.cellSize
    FocalOperation(self, n){ (tile, bounds) =>
      calc(tile, bounds, cellSize)
    }
  }
}