Updated ShowableTile to render NoData values differently.

Author: metasim

core/src/main/scala/org/locationtech/rasterframes/tiles/ShowableTile.scala

@@ -21,7 +21,7 @@
 
 package org.locationtech.rasterframes.tiles
 import org.locationtech.rasterframes._
-import geotrellis.raster.Tile
+import geotrellis.raster.{Tile, isNoData}
 
 class ShowableTile(val delegate: Tile) extends FixedDelegatingTile {
   override def equals(obj: Any): Boolean = obj match {
@@ -39,8 +39,14 @@ object ShowableTile {
     val dims = tile.dimensions
 
     val data = if (tile.cellType.isFloatingPoint)
-      tile.toArrayDouble()
-    else tile.toArray()
+      tile.toArrayDouble().map {
+        case c if isNoData(c) => "--"
+        case c => c.toString
+      }
+    else tile.toArray().map {
+      case c if isNoData(c) => "--"
+      case c => c.toString
+    }
 
     val cells = if(tile.size <= maxCells) {
       data.mkString("[", ",", "]")

core/src/test/scala/org/locationtech/rasterframes/TileUDTSpec.scala

@@ -20,7 +20,8 @@
  */
 
 package org.locationtech.rasterframes
-import geotrellis.raster.{CellType, Tile}
+import geotrellis.raster
+import geotrellis.raster.{CellType, NoNoData, Tile}
 import org.apache.spark.sql.catalyst.encoders.ExpressionEncoder
 import org.apache.spark.sql.rf._
 import org.apache.spark.sql.types.StringType
@@ -98,6 +99,12 @@ class TileUDTSpec extends TestEnvironment with TestData with Inspectors {
       forEveryConfig { tile =>
         val stringified = Seq(tile).toDF("tile").select($"tile".cast(StringType)).as[String].first()
         stringified should be(ShowableTile.show(tile))
+
+        if(!tile.cellType.isInstanceOf[NoNoData]) {
+          val withNd = tile.mutable
+          withNd.update(0, raster.NODATA)
+          ShowableTile.show(withNd) should include("--")
+        }
       }
     }
   }