Added utility for creating a GeoJSON structure for all the tile footprints in a RasterFrame.

Signed-off-by: Simeon H.K. Fitch <[email protected]>

Author: metasim

core/src/main/scala/astraea/spark/rasterframes/util/debug/package.scala

@@ -21,6 +21,10 @@
 package astraea.spark.rasterframes.util
 
 import astraea.spark.rasterframes._
+import geotrellis.proj4.LatLng
+import geotrellis.vector.{Feature, Geometry}
+import geotrellis.vector.io.json.JsonFeatureCollection
+import spray.json.JsValue
 
 /**
  * Additional debugging routines. No guarantees these are or will remain stable.
@@ -34,5 +38,19 @@ package object debug {
     def describeFullSchema: String = {
       self.schema.prettyJson
     }
+
+    /** Renders all the extents in this RasterFrame as GeoJSON in EPSG:4326. This does a full
+     * table scan and collects **all** the geometry into the driver, and then converts it into a
+     * Spray JSON data structure. Not performant, and for debugging only. */
+    def geoJsonExtents: JsValue = {
+      import spray.json.DefaultJsonProtocol._
+
+      val features = self
+        .select(BOUNDS_COLUMN, SPATIAL_KEY_COLUMN)
+        .collect()
+        .map{ case (p, s) ⇒ Feature(Geometry(p).reproject(self.crs, LatLng), Map("col" -> s.col, "row" -> s.row)) }
+
+      JsonFeatureCollection(features).toJson
+    }
   }
 }