我正在尝试使用示例http://docs.geotools.org/latest/userguide/tutorial/raster/image.html在 wms 层上覆盖 shp 文件。
我不断收到错误：
Exception in thread "main" java.lang.UnsupportedOperationException: Trying to get a reader from an unknown format.
at org.geotools.coverage.grid.io.UnknownFormat.getReader(UnknownFormat.java:62)
at com.qedrix.map.maplotr.Demo1.displayLayers(Demo1.java:121)
at com.qedrix.map.maplotr.Demo1.main(Demo1.java:229)
当代码尝试读取 WMS 图像时。
我的代码如下所示：
public class Demo1 {
private AbstractGridCoverage2DReader reader = null;
private StyleFactory sf = CommonFactoryFinder.getStyleFactory();
private FilterFactory2 ff = CommonFactoryFinder.getFilterFactory2();
/**
* This method examines the names of the sample dimensions in the provided
* coverage looking for "red...", "green..." and "blue..." (case insensitive
* match). If these names are not found it uses bands 1, 2, and 3 for the
* red, green and blue channels. It then sets up a raster symbolizer and
* returns this wrapped in a Style.
*
* @return a new Style object containing a raster symbolizer set up for RGB
* image
*/
private Style createRGBStyle() {
GridCoverage2D cov = null;
try {
cov = reader.read(null);
} catch (IOException giveUp) {
throw new RuntimeException(giveUp);
}
// We need at least three bands to create an RGB style
int numBands = cov.getNumSampleDimensions();
if (numBands < 3) {
return null;
}
// Get the names of the bands
String[] sampleDimensionNames = new String[numBands];
for (int i = 0; i < numBands; i++) {
GridSampleDimension dim = cov.getSampleDimension(i);
sampleDimensionNames[i] = dim.getDescription().toString();
}
final int RED = 0, GREEN = 1, BLUE = 2;
int[] channelNum = { -1, -1, -1 };
// We examine the band names looking for "red...", "green...",
// "blue...".
// Note that the channel numbers we record are indexed from 1, not 0.
for (int i = 0; i < numBands; i++) {
String name = sampleDimensionNames[i].toLowerCase();
if (name != null) {
if (name.matches("red.*")) {
channelNum[RED] = i + 1;
} else if (name.matches("green.*")) {
channelNum[GREEN] = i + 1;
} else if (name.matches("blue.*")) {
channelNum[BLUE] = i + 1;
}
}
}
// If we didn't find named bands "red...", "green...", "blue..."
// we fall back to using the first three bands in order
if (channelNum[RED] < 0 || channelNum[GREEN] < 0 || channelNum[BLUE] < 0) {
channelNum[RED] = 1;
channelNum[GREEN] = 2;
channelNum[BLUE] = 3;
}
// Now we create a RasterSymbolizer using the selected channels
SelectedChannelType[] sct = new SelectedChannelType[cov.getNumSampleDimensions()];
ContrastEnhancement ce = sf.contrastEnhancement(ff.literal(1.0), ContrastMethod.NORMALIZE);
for (int i = 0; i < 3; i++) {
sct[i] = sf.createSelectedChannelType(String.valueOf(channelNum[i]), ce);
}
RasterSymbolizer sym = sf.getDefaultRasterSymbolizer();
ChannelSelection sel = sf.channelSelection(sct[RED], sct[GREEN], sct[BLUE]);
sym.setChannelSelection(sel);
return SLD.wrapSymbolizers(sym);
}
public void displayLayers() {
File rasterFile = fetchWmsImage();
AbstractGridFormat format = GridFormatFinder.findFormat(rasterFile);
this.reader = format.getReader(rasterFile);
// Initially display the raster in greyscale using the
// data from the first image band
Style rasterStyle = createRGBStyle();
// Create a basic style with yellow lines and no fill
Style shpStyle = SLD.createPointStyle("point", Color.YELLOW, Color.GRAY, 0.0f, 1.5f);
MapContent map = new MapContent();
map.setTitle("ImageLab");
MapViewport vp = new MapViewport();
org.geotools.map.Layer rasterLayer = new GridReaderLayer(reader, rasterStyle);
map.addLayer(rasterLayer);
saveImage(map, "final.jpeg", 583);
}
public File fetchWmsImage() {
URL url = null;
try {
url = new URL("http://184.106.187.247:8080/geoserver/rg/wms?version=1.1.0");
} catch (MalformedURLException e) {
// will not happen
}
WebMapServer wms = null;
try {
wms = new WebMapServer(url);
WMSCapabilities capabilities = wms.getCapabilities();
Layer[] layers = WMSUtils.getNamedLayers(capabilities);
GetMapRequest request = wms.createGetMapRequest();
request.setFormat("image/png");
request.setDimensions("583", "420");
request.setTransparent(true);
request.setSRS("EPSG:900913");
request.setBBox("-13019428.542822,3922163.1648461,-13013051.407366,3929863.8567165");
request.setProperty("isBaseLayer", "false");
request.setProperty("opacity", ".2");
for (Layer layer : WMSUtils.getNamedLayers(capabilities)) {
if (layer.getName().equals("rg:parcels"))
request.addLayer(layer);
}
GetMapResponse response = (GetMapResponse) wms.issueRequest(request);
BufferedImage image = ImageIO.read(response.getInputStream());
File rasterFile = new File("C:\\Users\\samabhik\\Workspace\\MAP\\data\\out.png");
ImageIO.write(image, "png", rasterFile);
return rasterFile;
} catch (ServiceException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
}
return null;
}
public void saveImage(final MapContent map, final String file, final int imageWidth) {
GTRenderer renderer = new StreamingRenderer();
renderer.setMapContent(map);
Rectangle imageBounds = null;
ReferencedEnvelope mapBounds = null;
try {
mapBounds = map.getMaxBounds();
double heightToWidth = mapBounds.getSpan(1) / mapBounds.getSpan(0);
imageBounds = new Rectangle(0, 0, imageWidth, (int) Math.round(imageWidth * heightToWidth));
} catch (Exception e) {
// failed to access map layers
throw new RuntimeException(e);
}
BufferedImage image = new BufferedImage(imageBounds.width, imageBounds.height, BufferedImage.TYPE_INT_RGB);
Graphics2D gr = image.createGraphics();
gr.setPaint(Color.WHITE);
gr.fill(imageBounds);
try {
renderer.paint(gr, imageBounds, mapBounds);
File fileToSave = new File(file);
ImageIO.write(image, "jpeg", fileToSave);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public static void main(String[] args) {
Demo1 demo = new Demo1();
demo.displayLayers();
}
}
我的 pom 依赖项如下所示：
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-shapefile</artifactId>
<version>${geotools.version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-swing</artifactId>
<version>${geotools.version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-epsg-hsql</artifactId>
<version>${geotools.version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-geotiff</artifactId>
<version>${geotools.version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-image</artifactId>
<version>${geotools.version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-wms</artifactId>
<version>${geotools.version}</version>
</dependency>
<dependency>
<groupId>org.geotools</groupId>
<artifactId>gt-coverage</artifactId>
<version>${geotools.version}</version>
</dependency>
我在某处读到它可能是 GDAL 问题。但我不知道如何解决它。我在 64 JDK 1.6 和 Win 7 amd64 上使用 eclipse。
请帮助，有人..
刚刚使用 GDAL 本机库路径中的 gdalinfo.exe 测试了图像文件。这是报告：
Driver: PNG/Portable Network Graphics
Files: ..\..\Workspace\MAP\data\out2.png
Size is 583, 420
Coordinate System is `'
Image Structure Metadata:
INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left ( 0.0, 0.0)
Lower Left ( 0.0, 420.0)
Upper Right ( 583.0, 0.0)
Lower Right ( 583.0, 420.0)
Center ( 291.5, 210.0)
Band 1 Block=583x1 Type=Byte, ColorInterp=Red
Mask Flags: PER_DATASET ALPHA
Band 2 Block=583x1 Type=Byte, ColorInterp=Green
Mask Flags: PER_DATASET ALPHA
Band 3 Block=583x1 Type=Byte, ColorInterp=Blue
Mask Flags: PER_DATASET ALPHA
Band 4 Block=583x1 Type=Byte, ColorInterp=Alpha
进一步更新
我刚刚尝试将 WMS 的输出格式从 images/png 更改为 images/geotiff，现在这部分工作（geotools 生成的最终图像是黑白）。为什么会这样？为什么它不适用于PNG？