Question

Null Pinter Exception只是意味着它是因为值变为null。但是如果使用像GeoTiff这样的APis，找出使用中的错误会很烦人。

我的代码如下：

System.out.println("vectorization starts");

GridCoverage2D srcCoverage = new GeoTiffReader(new File("E:/output/ll_processed.TIFF")).read(new GeneralParameterValue[]{policy, gridsize, useJaiRead});

SimpleFeatureCollection fc = RasterToVectorProcess.process(srcCoverage, 3, cov.getEnvelope(), Collections.singletonList(0.0d), true, null);

System.out.println("process ends");
System.out.println("vectorization ends");
//MapContext map = new DefaultMapContext();
//map.setTitle("raster to vector conversion");
Style style = SLD.createPolygonStyle(Color.BLUE, Color.CYAN, 1.0f);
//map.addLayer(fc, style);
//map.getLayerBounds();
//JMapFrame.showMap(map);

MapContent mapContent= new MapContent();
mapContent.setTitle("Illegal Mining");
Layer layer = new FeatureLayer(fc, style,"VectorLayer");

//int boundary = 10;
// ReferencedEnvelope env2 = new  ReferencedEnvelope(srcCoverage.getEnvelope().getMinimum(0) - boundary, srcCoverage.getEnvelope().getMaximum(0) + boundary,
    //srcCoverage.getEnvelope().getMinimum(1) - boundary, srcCoverage.getEnvelope().getMaximum(1) + boundary, srcCoverage.getCoordinateReferenceSystem());

//mapContent.getViewport().setBounds(fc.getBounds());
Line 199 : if(layer.getBounds()!=null) // here the error is coming also tried with if(layer != null && layer.getBounds()!=null) 
 {
    mapContent.addLayer(layer);
}else{
    System.out.println("Layer bounds are null");
}
mapContent.getViewport().setCoordinateReferenceSystem(
        DefaultGeographicCRS.WGS84);

错误

at org.geotools.map.FeatureLayer.getBounds（FeatureLayer.java:199）

我正在尝试将Tiff转换为Vector图像然后我想将其存储在磁盘上。

Answer 1

最有可能的是，您的featureSource为空，因为geotools FeatureLayer class方法getBounds()使用featureSource来检索边界，但在构造函数FeatureLayer中没有检查featureSource是否为null。

featureSource是FeatureLayer构造函数的第一个参数。在您的情况下，这是变量SimpleFeatureCollection fc。

最有可能的是，方法process.process返回null，因此fc为空。

RasterToVectorProcess.java中的次要更改

       //features.add(builder.buildFeature(null));
                //System.out.println("ignored");
                //add
                System.out.println("adding...");
                SimpleFeature feature = builder.buildFeature(null);
                ((Collection<SimpleFeature>) features).add(feature);

要素图层使用从RasterToVectorProcess派生的featurecollection获取空边界

1 个答案: