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Clip Worker

Processes clip operations to extract features within a boundary.

Overview

The clip worker extracts features from a dataset that intersect with a clipping boundary geometry.

Job Type

clip

Input Parameters

{
  "dataset_id": 123,
  "clip_geometry": {
    "type": "Polygon",
    "coordinates": [ ... ]
  },
  "output_dataset_id": 124
}

Parameters

dataset_id (required): Source dataset ID
clip_geometry (required): GeoJSON geometry for clipping boundary
output_dataset_id (required): Output dataset ID

Output

Creates a new dataset with clipped features:

Features that intersect the clipping boundary
Geometry clipped to boundary
Original attributes preserved

Algorithm

The worker uses PostGIS ST_Intersection to:

Transform clipping geometry to dataset SRID
Find features that intersect the boundary
Clip geometries to boundary
Store results in output table

Example

# Enqueue a clip job via API
curl -X POST "https://example.com/api/datasets_clip_run.php" \
  -H "Content-Type: application/json" \
  -d '{
    "dataset_id": 123,
    "clip_geometry": {
      "type": "Polygon",
      "coordinates": [[[-180, -90], [180, -90], [180, 90], [-180, 90], [-180, -90]]]
    },
    "output_dataset_id": 124
  }'

Background Jobs

This analysis runs as a background job. The worker:

Fetches queued clip jobs
Validates input parameters
Executes PostGIS clip queries
Creates output dataset
Marks job as completed

Performance Considerations

Processing time depends on dataset size and boundary complexity
Complex clipping boundaries may slow processing
Spatial indexes improve intersection performance
Consider simplifying geometries before clipping

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