Geotools OSM瓦片层加载图像失败，无法创建ImageInputStream。

Question

我试图使用geotools和瓷砖客户端在给定的边界框中打印一个OSM瓷砖，我已经实现了一个wms服务，可以读取wms请求并在给定的边界框中渲染图像，OSM层被用作基础层，我有其他层是矢量层，我可以稍后添加，矢量层在给定的边界框中正确显示，但OSM瓷砖没有显示，用于发送请求到OSM服务器的Url没有得到任何响应，我有以下错误。

2020-05-27 16:03:00.291 ERROR 26094 --- [pool-6-thread-1] org.geotools.tile                        : Failed to load image: https://tile.openstreetmap.org/8/123/106.png

java.io.IOException: Can't create an ImageInputStream!
    at org.geotools.image.io.ImageIOExt.read(ImageIOExt.java:339) ~[gt-coverage-22.2.jar:na]
    at org.geotools.image.io.ImageIOExt.readBufferedImage(ImageIOExt.java:402) ~[gt-coverage-22.2.jar:na]
    at org.geotools.tile.Tile.loadImageTileImage(Tile.java:175) ~[gt-tile-client-22.2.jar:na]
    at org.geotools.tile.Tile.getBufferedImage(Tile.java:163) ~[gt-tile-client-22.2.jar:na]
    at org.geotools.tile.util.TileLayer.getTileImage(TileLayer.java:143) [gt-tile-client-22.2.jar:na]
    at org.geotools.tile.util.TileLayer.renderTile(TileLayer.java:131) [gt-tile-client-22.2.jar:na]
    at org.geotools.tile.util.TileLayer.renderTiles(TileLayer.java:125) [gt-tile-client-22.2.jar:na]
    at org.geotools.tile.util.TileLayer.draw(TileLayer.java:86) [gt-tile-client-22.2.jar:na]
    at org.geotools.renderer.lite.CompositingGroup$WrappingDirectLayer.draw(CompositingGroup.java:228) [gt-render-22.2.jar:na]
    at org.geotools.renderer.lite.StreamingRenderer$RenderDirectLayerRequest.execute(StreamingRenderer.java:3850) [gt-render-22.2.jar:na]
    at org.geotools.renderer.lite.StreamingRenderer$PainterThread.run(StreamingRenderer.java:3911) [gt-render-22.2.jar:na]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_232]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_232]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_232]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_232]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_232]

对于源码来说，这些是我如何添加OMS瓦片层的。

MapContent mapContent = new MapContent();
String baseURL = "https://tile.openstreetmap.org/";
TileService service = new OSMService("OSM", baseURL);
mapContent.addLayer(new TileLayer(service));

后来我用gt-render打印它。

StreamingRenderer renderer = new StreamingRenderer();
renderer.setMapContent(map);
ReferencedEnvelope mapBounds = mapRequest.getReferencedEnvelope();
Rectangle imageBounds = new Rectangle(0, 0, mapRequest.getWidth(), mapRequest.getHeight());

map.getViewport().setScreenArea(imageBounds);
map.getViewport().setBounds( mapBounds );

BufferedImage image = new BufferedImage(mapRequest.getWidth(), mapRequest.getHeight(),BufferedImage.TYPE_4BYTE_ABGR);
Graphics2D gr = image.createGraphics();

gr.setRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));

int threads = Runtime.getRuntime().availableProcessors();
ExecutorService fixedPool = Executors.newFixedThreadPool(threads - 1);
        renderer.setThreadPool(fixedPool);

try {
        renderer.paint(gr, imageBounds, mapBounds);
        ImageIO.write(image, imageExtension, os);
    } 
catch (IOException e) {
            throw new RuntimeException(e);
    }

gr.dispose();
map.dispose();

我有一个硬编码版本的源代码来测试它。

  public void test(OutputStream os) throws NoSuchAuthorityCodeException, FactoryException {

        MapContent map = new MapContent();

        String baseURL = "https://tile.openstreetmap.org/";
        TileService service = new OSMService("OSM", baseURL);
        map.addLayer(new TileLayer(service));

        StreamingRenderer renderer = new StreamingRenderer();
        renderer.setMapContent(map);

        CoordinateReferenceSystem crs = CRS.decode("EPSG:3857");

        ReferencedEnvelope mapBounds = new ReferencedEnvelope(-939258.203568246,-626172.1357121639,3130860.67856082,3443946.746416902,crs);
        Rectangle imageBounds = new Rectangle(0, 0, 256, 256);

        map.getViewport().setScreenArea(imageBounds);
        map.getViewport().setBounds( mapBounds );

        BufferedImage image = new BufferedImage(256, 256,
                BufferedImage.TYPE_4BYTE_ABGR);
        Graphics2D gr = image.createGraphics();

        gr.setRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));

        try {
            renderer.paint(gr, imageBounds, mapBounds);
            ImageIO.write(image, imageExtension, os);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        gr.dispose();
        map.dispose();
    }

Answer 1

问题似乎是OpenStreetMap会返回一个HTTP-429错误(Too Many Requests)，如果你不设置一个 "请求太多"(Too Many Requests)。在您的请求中使用有效的用户代理头。.

我假设这是一个新的要求，因为OSM磁贴代码最后一次使用或测试。虽然从测试的情况来看，它可能并没有真正地获取一个瓷砖来渲染。

我已经 提出了一个针对 gt-tile-client 在 问题追踪器 而我有 PR来解决这个问题，添加一个头作为 WMTSTile 实施 确实如此。

它应该可以在今天晚些时候的主年夜建30520。