public static void makeHeatmap(int radius) throws Exception {     Scanner scan = new Scanner(new File("/Users/leijurv/Downloads/heatmap_overworld_full.csv"));     // from -radius to +radius-1     BufferedImage output = new BufferedImage(radius * 2, radius * 2, BufferedImage.TYPE_BYTE_GRAY);     WritableRaster raster = output.getRaster();     SampleModel model = raster.getSampleModel();     DataBuffer buffer = raster.getDataBuffer();     for (int x = 0; x < 2 * radius; x++) {         for (int y = 0; y < 2 * radius; y++) {             model.setSample(x, y, 0, 255, buffer);         }     }     int i = 0;     while (scan.hasNextLine()) {         if (++i % 1000000 == 0) {             System.out.println(i);         }         String line = scan.nextLine();         String[] split = line.split(",");         int chunkX = Integer.parseInt(split[0]);         int chunkZ = Integer.parseInt(split[1]);         int imageX = chunkX + radius;         int imageY = chunkZ + radius;         if (imageX < 0 || imageX >= 2 * radius || imageY < 0 || imageY >= 2 * radius) {             continue;         }         int weight = Integer.parseInt(split[2]);         int color = 255 - (int) (50 * Math.log(weight)) - 50;         if (color < 0) {             color = 0;         }         if (color > 255) {             color = 255;         }         model.setSample(imageX, imageY, 0, color, buffer);     }     File o = new File("/Users/leijurv/Downloads/heatmap_overworld_full.png");     ImageIO.write(output, "png", o); }