Read Multiplex Band Support

docs/guides/core-concepts.rst

@@ -301,3 +301,58 @@ intersects it. The higher the ``zindex``, the more priority it has.
 
   # Will always be selected
   feature3 = gps.Feature(geometry=geom3, properties=cell_value3)
+
+SourceInfo
+-----------
+
+:class:`~geopyspark.geotrellis.SourceInfo` represents a data source and the
+information on how that data should be read in.
+
+Reading from Singleband Data Sources
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For example, suppose that one wants to calculate NDVI for an area, and the bands that
+represent the red and near infrared (NIR) values are in two seperate files: ``red_band.tiff``
+and ``nir_band.tiff``, respectively. To read in these files as a single ``Tile`` (ie. a
+``Tile`` with two bands), we can specify our ``SourceInfo``\s as:
+
+.. code:: python3
+
+  source_1 = gps.SourceInfo("/tmp/red_band.tiff", {0: 0})
+  source_2 = gps.SourceInfo("/tmp/nir_band.tiff" {0: 1})
+
+
+``source_1`` states that ``Tile``\s created from ``red_band.tiff`` will use the
+data from band ``0`` of the source for its band ``0``. Whereas ``Tile``\s created
+from ``source_2`` will have the band ``0`` of the source be band ``1`` of the
+``Tile``. Thus, when ``red_band.tiff`` and ``nir_band.tiff`` intersect the
+same area, the resulting ``Tile``\(s) will have two bands: ``0`` from ``red_band.tiff``
+and ``1`` from ``nir_band.tiff``.
+
+Reading from Multiband Data Sources
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+It is also possible to read in individual bands from a multiband data source.
+Continuing the example above, suppose one wants to calculate NDVI using
+Landsat 8 data where each file contains all eleven bands. In this case,
+only the red band (band ``3``) and the NIR band (band ``4``) are of interest.
+We can read in just those bands by doing:
+
+.. code:: python3
+
+  source = gps.SourceInfo("/tmp/all-landsat-bands.tiff", {3: 0, 4: 1})
+
+The above source will have just bands ``3`` and ``4`` read in, and the resulting
+``Tile``\s will just have two bands: the first from ``3`` and the second from
+``4``, respectively.
+
+A Note on Missing Data
+~~~~~~~~~~~~~~~~~~~~~~~
+
+In the event that data of a specified band does not exist in a region, the
+resulting ``Tile``\(s) of that area will have that band be composed of ``NoData``
+values.
+
+So if the ``nir_band.tiff`` covers a smaller area than the ``red_band.tiff``,
+the ``Tile``\(s) of those uncovered regions will have their band ``1`` be
+just ``NoData`` values.

geopyspark-backend/geotrellis/src/main/scala/geopyspark/geotrellis/vlm/RasterSource.scala

@@ -1,7 +1,7 @@
 package geopyspark.geotrellis.vlm
 
-import geopyspark.geotrellis.{PartitionStrategy, ProjectedRasterLayer, SpatialTiledRasterLayer}
-import geopyspark.geotrellis.{LayoutType => GPSLayoutType, LocalLayout => GPSLocalLayout, GlobalLayout => GPSGlobalLayout, SpatialTiledRasterLayer}
+import geopyspark.geotrellis.{PartitionStrategy, ProjectedRasterLayer, SpatialTiledRasterLayer, SpatialPartitioner}
+import geopyspark.geotrellis.{LayoutType => GPSLayoutType, LocalLayout => GPSLocalLayout, GlobalLayout => GPSGlobalLayout}
 
 import geopyspark.geotrellis.Constants.{GEOTRELLIS, GDAL}
 
@@ -17,7 +17,7 @@ import geotrellis.proj4._
 import geotrellis.vector._
 import geotrellis.util._
 
-import org.apache.spark.SparkContext
+import org.apache.spark.{SparkContext, Partitioner}
 import org.apache.spark.rdd.RDD
 
 import scala.collection.JavaConverters._
@@ -29,17 +29,27 @@ object RasterSource {
     layerType: String,
     paths: java.util.ArrayList[String],
     targetCRS: String,
+    numPartitions: Integer,
     resampleMethod: ResampleMethod,
     readMethod: String
-  ): ProjectedRasterLayer =
+  ): ProjectedRasterLayer = {
+    val scalaPaths: Seq[String] = paths.asScala.toSeq
+
+    val partitions =
+      numPartitions match {
+        case i: Integer => Some(i.toInt)
+        case null => None
+      }
+
     read(
       sc,
       layerType,
-      sc.parallelize(paths.asScala),
+      sc.parallelize(scalaPaths, partitions.getOrElse(scalaPaths.size)),
       targetCRS,
       resampleMethod,
       readMethod
     )
+  }
 
   def read(
     sc: SparkContext,
@@ -51,7 +61,7 @@ object RasterSource {
   ): ProjectedRasterLayer = {
     val rasterSourceRDD: RDD[RasterSource] =
       (readMethod match {
-        case GEOTRELLIS => rdd.map { GeoTiffRasterSource(_): RasterSource }
+        case GEOTRELLIS => rdd.map { new GeoTiffRasterSource(_): RasterSource }
         case GDAL => rdd.map { GDALRasterSource(_): RasterSource }
       }).cache()
 
@@ -82,18 +92,28 @@ object RasterSource {
     paths: java.util.ArrayList[String],
     layoutType: GPSLayoutType,
     targetCRS: String,
+    numPartitions: Integer,
     resampleMethod: ResampleMethod,
     readMethod: String
-  ): SpatialTiledRasterLayer =
+  ): SpatialTiledRasterLayer = {
+    val scalaPaths: Seq[String] = paths.asScala.toSeq
+
+    val partitions =
+      numPartitions match {
+        case i: Integer => Some(i.toInt)
+        case null => None
+      }
+
     readToLayout(
       sc,
       layerType,
-      sc.parallelize(paths.asScala),
+      sc.parallelize(scalaPaths, partitions.getOrElse(scalaPaths.size)),
       layoutType,
       targetCRS,
       resampleMethod,
       readMethod
     )
+  }
 
   def readToLayout(
     sc: SparkContext,
@@ -147,7 +167,91 @@ object RasterSource {
     val contextRDD: MultibandTileLayerRDD[SpatialKey] =
       ContextRDD(tiledRDD, tileLayerMetadata)
 
-    SpatialTiledRasterLayer(zoom.toInt, contextRDD)
+    SpatialTiledRasterLayer(zoom, contextRDD)
+  }
+
+  def readOrderedToLayout(
+    sc: SparkContext,
+    paths: java.util.ArrayList[SourceInfo],
+    layoutType: GPSLayoutType,
+    targetCRS: String,
+    numPartitions: Integer,
+    resampleMethod: ResampleMethod,
+    partitionStrategy: PartitionStrategy,
+    readMethod: String
+  ): SpatialTiledRasterLayer = {
+    val scalaSources: Seq[SourceInfo] = paths.asScala.toSeq
+
+    val partitions =
+      numPartitions match {
+        case i: Integer => Some(i.toInt)
+        case null => None
+      }
+
+    val partitioner: Option[Partitioner] =
+      partitionStrategy match {
+        case ps: PartitionStrategy => ps.producePartitioner(partitions.getOrElse(scalaSources.size))
+        case null => None
+      }
+
+    val crs: Option[CRS] =
+      targetCRS match {
+        case crs: String => Some(CRS.fromString(crs))
+        case null => None
+      }
+
+    val transformSource: String => RasterSource =
+      readMethod match {
+        case GEOTRELLIS =>
+          crs match {
+            case Some(projection) =>
+              (path: String) => GeoTiffRasterSource(path).reproject(projection, resampleMethod)
+            case None =>
+              (path: String) => GeoTiffRasterSource(path)
+          }
+        case GDAL =>
+          crs match {
+            case Some(projection) =>
+              (path: String) => GDALRasterSource(path).reproject(projection, resampleMethod)
+            case None =>
+              (path: String) => GDALRasterSource(path)
+          }
+      }
+
+    val sourceInfoRDD: RDD[SourceInfo] =
+      sc.parallelize(scalaSources, partitions.getOrElse(scalaSources.size))
+
+    val readingSourcesRDD: RDD[ReadingSource] =
+      sourceInfoRDD.map { source =>
+        val rasterSource = transformSource(source.source)
+
+        ReadingSource(rasterSource, source.sourceToTargetBand)
+      }
+
+    val sourcesRDD: RDD[RasterSource] = readingSourcesRDD.map { _.source }
+
+    val rasterSummary: RasterSummary = geotrellis.contrib.vlm.RasterSummary.fromRDD(sourcesRDD)
+
+    val LayoutLevel(zoom, layout) =
+      layoutType match {
+        case global: GPSGlobalLayout =>
+          val scheme = ZoomedLayoutScheme(rasterSummary.crs, global.tileSize)
+          scheme.levelForZoom(global.zoom)
+        case local: GPSLocalLayout =>
+          val scheme = FloatingLayoutScheme(local.tileCols, local.tileRows)
+          rasterSummary.levelFor(scheme)
+      }
+
+    val resampledSourcesRDD: RDD[ReadingSource] =
+      readingSourcesRDD.map { source =>
+        val resampledSource: RasterSource = source.source.resampleToGrid(layout, resampleMethod)
+
+        source.copy(source = resampledSource)
+      }
+
+    val result = RasterSourceRDD.read(resampledSourcesRDD, layout, partitioner)(sc)
+
+    SpatialTiledRasterLayer(zoom, result)
   }
 
   implicit def gps2VLM(layoutType: GPSLayoutType): LayoutType =

geopyspark-backend/geotrellis/src/main/scala/geopyspark/geotrellis/vlm/SourceInfo.scala

@@ -0,0 +1,21 @@
+package geopyspark.geotrellis.vlm
+
+import scala.collection.JavaConverters._
+
+
+case class SourceInfo(
+  source: String,
+  sourceToTargetBand: Map[Int, Int]
+) extends Serializable
+
+
+object SourceInfo {
+  def apply(source: String, sourceBand: Int, targetBand: Int): SourceInfo =
+    SourceInfo(source, Map(sourceBand -> targetBand))
+
+  def apply(source: String, targetBand: Int): SourceInfo =
+    SourceInfo(source, 0, targetBand)
+
+  def apply(source: String, javaMap: java.util.HashMap[Int, Int]): SourceInfo =
+    SourceInfo(source, javaMap.asScala.toMap)
+}

geopyspark-backend/project/plugins.sbt

@@ -4,6 +4,7 @@ resolvers ++= Seq(
 )
 
 addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.9.0")
-addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.5")
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.9")
+
 addSbtPlugin("org.foundweekends" % "sbt-bintray" % "0.5.2")
 addSbtPlugin("io.get-coursier" % "sbt-coursier" % "1.1.0-M10")

geopyspark-backend/project/protoc.sbt

@@ -0,0 +1,3 @@
+addSbtPlugin("com.thesamet" % "sbt-protoc" % "0.99.15")
+
+libraryDependencies += "com.thesamet.scalapb" %% "compilerplugin" % "0.7.0"

geopyspark/geotrellis/__init__.py

@@ -646,6 +646,33 @@ def __new__(cls, time_unit, num_partitions=None, bits=8, time_resolution=None):
         return super(cls, SpaceTimePartitionStrategy).__new__(cls, time_unit, num_partitions, bits, time_resolution)
 
 
+class SourceInfo(namedtuple("SourceInfo", "source source_to_target_band")):
+    """Represents a data source and how its bands should be formatted when being read
+    in.
+
+    When two or more sources of data cover the same area, a single ``Tile`` will be created
+    that contains the bands specified by ``source_to_target_band``.
+
+    Args:
+        source (str): The path to the data source to be read.
+        source_to_target_band ({int: int}): A ``{int: int}`` that maps each band from the
+            source to the target band of the output.
+
+            For example, ``{0: 2}`` specifies that band ``0`` of the source be band ``2``
+            for the ``Tile``\s that were created from that source.
+    Attributes:
+        source (str): The path to the data source to be read.
+        source_to_target_band ({int: int}): A ``{int: int}`` that maps each band from the
+            source to the target band of the output.
+
+            For example, ``{0: 2}`` specifies that band ``0`` of the source be band ``2``
+            for the ``Tile``\s that were created from that source.
+
+    """
+
+    __slots__ = []
+
+
 class Feature(namedtuple("Feature", "geometry properties")):
     """Represents a geometry that is derived from an OSM Element with that Element's associated metadata.
 
@@ -834,7 +861,7 @@ def __str__(self):
 __all__ = ["Tile", "Extent", "ProjectedExtent", "TemporalProjectedExtent", "SpatialKey", "SpaceTimeKey",
            "Metadata", "TileLayout", "GlobalLayout", "LocalLayout", "LayoutDefinition", "Bounds", "RasterizerOptions",
            "zfactor_lat_lng_calculator", "zfactor_calculator", "HashPartitionStrategy", "SpatialPartitionStrategy",
-           "SpaceTimePartitionStrategy", "Feature", "CellValue"]
+           "SpaceTimePartitionStrategy", "Feature", "CellValue", "SourceInfo"]
 
 from . import catalog
 from . import color

geopyspark/geotrellis/converters.py

@@ -9,7 +9,8 @@
                                    LayoutDefinition,
                                    HashPartitionStrategy,
                                    SpatialPartitionStrategy,
-                                   SpaceTimePartitionStrategy)
+                                   SpaceTimePartitionStrategy,
+                                   SourceInfo)
 
 
 from geopyspark.geotrellis.constants import ResampleMethod
@@ -148,6 +149,16 @@ def convert(self, obj, gateway_client):
         return ScalaTemporalStrategy.apply(obj.num_partitions, obj.bits, scala_time_unit, scala_time_resolution)
 
 
+class SourceInfoConverter(object):
+    def can_convert(self, object):
+        return isinstance(object, SourceInfo)
+
+    def convert(self, obj, gateway_client):
+        ScalaSourceInfo = JavaClass("geopyspark.geotrellis.vlm.SourceInfo", gateway_client)
+
+        return ScalaSourceInfo.apply(obj.source, obj.source_to_target_band)
+
+
 register_input_converter(CellTypeConverter(), prepend=True)
 register_input_converter(RasterizerOptionsConverter(), prepend=True)
 register_input_converter(LayoutTypeConverter(), prepend=True)
@@ -156,3 +167,4 @@ def convert(self, obj, gateway_client):
 register_input_converter(HashPartitionStrategyConverter(), prepend=True)
 register_input_converter(SpatialPartitionStrategyConverter(), prepend=True)
 register_input_converter(SpaceTimePartitionStrategyConverter(), prepend=True)
+register_input_converter(SourceInfoConverter(), prepend=True)