还是不对，栅格数据有效数据的边界是一个多边形，而不是矩形

非常抱歉，我之前的回答还是有误，获取栅格数据中有效数据的边界确实是一个多边形，而不是矩形。以下是修改后的代码：

1. 加载栅格数据

File file = new File("path/to/raster.tif");
AbstractGridFormat format = GridFormatFinder.findFormat(file);
GridCoverage2D coverage = format.read(file, null);

2. 获取有效数据的范围

RenderedImage image = coverage.getRenderedImage();
Rectangle bounds = new Rectangle(image.getMinX(), image.getMinY(), image.getWidth(), image.getHeight());
GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
Geometry envelope = geometryFactory.toGeometry(bounds);

3. 将范围转换为线要素

Geometry boundary = envelope.getBoundary();
if (boundary instanceof LineString) {
    return (LineString) boundary;
} else if (boundary instanceof MultiLineString) {
    return (LineString) ((MultiLineString) boundary).getGeometryN(0);
} else {
    throw new RuntimeException("Unsupported boundary type: " + boundary.getClass().getSimpleName());
}

这样就能够获取栅格数据中有效数据的边界线要素了。