Add natural earth raster mbtile example

Author: jericks

examples/naturalearth_raster_mbtiles.groovy

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+import geoscript.geom.Bounds
+import geoscript.layer.Format
+import geoscript.layer.GeoTIFF
+import geoscript.layer.MBTiles
+import geoscript.layer.Raster
+import geoscript.layer.RasterTileRenderer
+import geoscript.layer.TileGenerator
+import geoscript.proj.Projection
+
+import static geoscript.GeoScript.download
+import static geoscript.GeoScript.unzip
+
+// Download data from natural earth
+File dataDir = new File("naturalearth")
+String url = "https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/raster/NE2_50M_SR_W.zip"
+unzip(download(new URL(url), new File(dataDir, "NE2_50M_SR_W.zip"), overwrite: false))
+
+// Raster Raster, crop and project
+Format format = new GeoTIFF(new File(dataDir, "NE2_50M_SR_W/NE2_50M_SR_W.tif"))
+Raster raster = format.read()
+Raster croppedRaster = raster.crop(new Bounds(-179.99, -85.0511, 179.99, 85.0511, new Projection("EPSG:4326")))
+Raster projectedRaster = croppedRaster.reproject(new Projection("EPSG:3857"))
+
+// Generate Tiles
+TileGenerator generator = new TileGenerator(verbose: true)
+MBTiles mbtiles = new MBTiles(new File("NE2_50M_SR_W.mbtiles"), "NE2_50M_SR_W", "Natural Earth II with Shaded Relief and Water")
+RasterTileRenderer renderer = new RasterTileRenderer(projectedRaster)
+generator.generate(mbtiles, renderer, 0, 6)