{
    "image_id": "sample_001",
    "classes": ["water", "forest", "urban", "agriculture", "barren"],
    "regions": [
        {
            "class": "urban",
            "polygon": [[100, 100], [200, 100], [200, 200], [100, 200]],
            "area": 10000.0
        },
        {
            "class": "forest",
            "polygon": [[300, 150], [450, 150], [450, 300], [300, 300]],
            "area": 22500.0
        },
        {
            "class": "water",
            "polygon": [[50, 250], [150, 250], [150, 350], [50, 350]],
            "area": 10000.0
        }
    ]
}