# Image Document

## Purpose
Raster imagery to be rendered as a map layer or thumbnail (e.g., amplitude σ0, coherence, classifications).

## GeoJSON (DB metadata)
```json
{
  "type": "Feature",
  "geometry": {"type": "Polygon", "coordinates": [[[30.1, 59.9], [30.2, 59.9], [30.2, 60.0], [30.1, 60.0], [30.1, 59.9]]]},
  "properties": {
    "type": "Image",
    "title": "Amplitude σ0",
    "created_at": "2025-09-02T12:00:00Z",
    "updated_at": "2025-09-02T12:05:00Z",
    "source": {
      "url": "/tiler/tiles/{z}/{x}/{y}@2x",
      "type": "Raster",
      "url_params": {
        "url": "s3://<bucket>/<ResultKey>/<filename>" 
      }
    },
    "style": {"colormap": "gray"},
    "legend": {"title": "Amplitude"},
    "metadata": {"sensor": "S1A", "gsd": 10}
  }
}
```

## Required properties
- `properties.type` = `Image`
- Footprint geometry (Polygon or MultiPolygon)
- Valid raster source URL (direct COG or tiler endpoint)

## Publishing workflow
1. Produce georeferenced raster (prefer COG with overviews).
2. Upload to object storage or tile service.
3. Publish GeoJSON Feature with type `Image` referencing raster in `properties.source.url`.

## Validation checklist
- Raster is georeferenced and in a supported projection.
- COG has internal overviews and correct tiling.
- Footprint matches raster extent.

See [Common properties](../common.md) for shared fields like legend, metadata, and classification.
See also: [GeoJSON Strategy](../../Geojson_strategy.md) and [Upload Strategy](../../Upload_strategy.md).