Raster Clip Worker

Processes raster clip operations to extract raster data within a boundary.

Overview

The raster clip worker extracts raster data that intersects with a clipping boundary geometry.

Job Type

raster_clip

Input Parameters

{
  "raster_dataset_id": 125,
  "clip_geometry": {
    "type": "Polygon",
    "coordinates": [ ... ]
  },
  "output_dataset_id": 126
}

Parameters

  • raster_dataset_id (required): Source raster dataset ID

  • clip_geometry (required): GeoJSON geometry for clipping boundary

  • output_dataset_id (required): Output raster dataset ID

Output

Creates a new raster dataset with clipped data:

  • Raster data within the clipping boundary

  • Original raster properties preserved

  • Proper spatial reference maintained

Algorithm

The worker uses PostGIS raster functions to:

  1. Transform clipping geometry to raster SRID

  2. Clip raster to boundary using ST_Clip

  3. Store clipped raster in output table

  4. Update raster metadata

Example

# Enqueue a raster clip job via API
curl -X POST "https://example.com/api/raster_clip_run.php" \
  -H "Content-Type: application/json" \
  -d '{
    "raster_dataset_id": 125,
    "clip_geometry": {
      "type": "Polygon",
      "coordinates": [[[-180, -90], [180, -90], [180, 90], [-180, 90], [-180, -90]]]
    },
    "output_dataset_id": 126
  }'

Background Jobs

This analysis runs as a background job. The worker:

  1. Fetches queued raster_clip jobs

  2. Validates input parameters

  3. Executes PostGIS raster clip operations

  4. Creates output raster dataset

  5. Marks job as completed

Performance Considerations

  • Processing time depends on raster size and boundary complexity

  • Large rasters may require significant memory

  • Consider resampling for very large rasters

  • Clipping boundaries should match raster resolution