v0.2.49..v0.2.50 changeset TileUtils.h

diff --git a/hoot-core/src/main/cpp/hoot/core/conflate/tile/TileUtils.h b/hoot-core/src/main/cpp/hoot/core/conflate/tile/TileUtils.h
new file mode 100644
index 0000000..565f4c2
--- /dev/null
+++ b/hoot-core/src/main/cpp/hoot/core/conflate/tile/TileUtils.h
@@ -0,0 +1,135 @@
+/*
+ * This file is part of Hootenanny.
+ *
+ * Hootenanny is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * --------------------------------------------------------------------
+ *
+ * The following copyright notices are generated automatically. If you
+ * have a new notice to add, please use the format:
+ * " * @copyright Copyright ..."
+ * This will properly maintain the copyright information. DigitalGlobe
+ * copyrights will be updated automatically.
+ *
+ * @copyright Copyright (C) 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ */
+
+#ifndef TILE_UTILS_H
+#define TILE_UTILS_H
+
+// GEOS
+#include <geos/geom/Envelope.h>
+
+// Hoot
+#include <hoot/core/elements/OsmMap.h>
+
+namespace hoot
+{
+
+/**
+ * Utilities for dealing with node density based tiles
+ */
+class TileUtils
+{
+public:
+
+  static std::string className() { return "hoot::TileUtils"; }
+
+  /**
+   * Calculates a set of boundary tiles
+   *
+   * @param maxNodesPerTile the requested maximum number of nodes to be in any one tile
+   * @param pixelSize the pixel size used to calculate the boundaries
+   * @param map the map containing the nodes
+   * @param minNodeCountInOneTile the smallest number of nodes actually found in any one tile
+   * @param maxNodeCountInOneTile the largest number of nodes actually found in any one tile
+   * @param nodeCounts a collection to store the number of node counts for each computed tile
+   * @return a grid of tile bounding boxes
+   */
+  static std::vector<std::vector<geos::geom::Envelope>>  calculateTiles(
+    const long maxNodesPerTile, const double pixelSize, OsmMapPtr map,
+    long& minNodeCountInOneTile, long& maxNodeCountInOneTile,
+    std::vector<std::vector<long>>& nodeCounts);
+
+  /**
+   * Retrieves a random tile index from a collection of tiles
+   *
+   * @param tiles the collection of tiles to calculate a random index for
+   * @param randomSeed optional random number generator seed
+   * @return an index
+   */
+  static int getRandomTileIndex(const std::vector<std::vector<geos::geom::Envelope>>& tiles,
+                                int randomSeed);
+
+  /**
+   * Retrieves a random boundary tile from a collection of tiles
+   *
+   * @param tiles the collection of tiles from which to select
+   * @param randomSeed optional random number generator seed
+   * @return a random tile selected from the computed tiles
+   */
+  static geos::geom::Envelope getRandomTile(
+    const std::vector<std::vector<geos::geom::Envelope>>& tiles, int randomSeed);
+
+  /**
+   * Writes boundary tiles to a GeoJSON output file
+   *
+   * @param tiles the collection of tiles to write
+   * @param nodeCounts a collection of the number of node counts for each computed tile
+   * @param outputPath the output file path
+   * @param selectSingleRandomTile
+   * @param randomSeed optional random number generator seed
+   * @todo collapse with OSM writing method and refactor to TileFootprintWriter?
+   * @todo refactor selectSingleRandomTile out?
+   */
+  static void writeTilesToGeoJson(const std::vector<std::vector<geos::geom::Envelope>>& tiles,
+                                  const std::vector<std::vector<long>>& nodeCounts,
+                                  const QString& outputPath,
+                                  const QString& fileSource = "",
+                                  const bool selectSingleRandomTile = false, int randomSeed = -1);
+
+  /**
+   * Writes boundary tiles to an OSM output file
+   *
+   * @param tiles the collection of tiles to write
+   * @param nodeCounts a collection of the number of node counts for each computed tile
+   * @param outputPath the output file path
+   * @param selectSingleRandomTile
+   * @param randomSeed optional random number generator seed
+   * @todo collapse with GeoJSON writing method and refactor to TileFootprintWriter?
+   * @todo refactor selectSingleRandomTile out?
+   */
+  static void writeTilesToOsm(
+    const std::vector<std::vector<geos::geom::Envelope>>& tiles,
+    const std::vector<std::vector<long>>& nodeCounts, const QString& outputPath,
+    const bool selectSingleRandomTile = false, int randomSeed = -1);
+
+private:
+
+  /**
+   * Convert boundary tiles to an OsmMap object
+   *
+   * @param tiles the collection of tiles to write
+   * @param nodeCounts a collection of the number of node counts for each computed tile
+   * @param randomTileIndex index of the random tile to use
+   * @param selectSingleRandomTile
+   */
+  static OsmMapPtr tilesToOsmMap(const std::vector<std::vector<geos::geom::Envelope>>& tiles,
+    const std::vector<std::vector<long>>& nodeCounts,
+    int randomTileIndex, const bool selectSingleRandomTile = false);
+};
+
+}
+
+#endif // TILE_UTILS_H