PostGIS
Mobile
QGIS
MapBender
GeoServer
GeoNode
GeoNetwork
Novella
Solutions
88 lines
2.0 KiB
Markdown
88 lines
2.0 KiB
Markdown
# Raster Clip Worker
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Processes raster clip operations to extract raster data within a boundary.
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## Overview
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The raster clip worker extracts raster data that intersects with a clipping boundary geometry.
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## Job Type
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`raster_clip`
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## Input Parameters
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```json
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{
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"raster_dataset_id": 125,
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"clip_geometry": {
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"type": "Polygon",
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"coordinates": [ ... ]
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},
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"output_dataset_id": 126
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}
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```
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### Parameters
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- `raster_dataset_id` (required): Source raster dataset ID
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- `clip_geometry` (required): GeoJSON geometry for clipping boundary
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- `output_dataset_id` (required): Output raster dataset ID
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## Output
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Creates a new raster dataset with clipped data:
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- Raster data within the clipping boundary
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- Original raster properties preserved
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- Proper spatial reference maintained
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## Algorithm
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The worker uses PostGIS raster functions to:
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1. Transform clipping geometry to raster SRID
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2. Clip raster to boundary using `ST_Clip`
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3. Store clipped raster in output table
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4. Update raster metadata
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## Example
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```bash
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# Enqueue a raster clip job via API
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curl -X POST "https://example.com/api/raster_clip_run.php" \
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-H "Content-Type: application/json" \
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-d '{
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"raster_dataset_id": 125,
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"clip_geometry": {
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"type": "Polygon",
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"coordinates": [[[-180, -90], [180, -90], [180, 90], [-180, 90], [-180, -90]]]
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},
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"output_dataset_id": 126
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}'
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```
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## Background Jobs
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This analysis runs as a background job. The worker:
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1. Fetches queued `raster_clip` jobs
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2. Validates input parameters
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3. Executes PostGIS raster clip operations
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4. Creates output raster dataset
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5. Marks job as completed
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## Performance Considerations
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- Processing time depends on raster size and boundary complexity
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- Large rasters may require significant memory
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- Consider resampling for very large rasters
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- Clipping boundaries should match raster resolution
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## Related Documentation
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- [Raster Tools](../analysis-tools/raster.md)
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- [Analysis API](../api/analysis.md)
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- [Workers Overview](index.md)
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