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Dissolve Worker

Processes dissolve operations to merge features based on attribute values.

Overview

The dissolve worker merges adjacent or overlapping features that share the same attribute value, optionally aggregating numeric fields.

Job Type

dissolve

Input Parameters

{
  "source_dataset_id": 123,
  "output_dataset_id": 124,
  "dissolve_mode": "field",
  "dissolve_field": "category",
  "aggregation_fields": {
    "population": "sum",
    "area": "sum"
  }
}

Parameters

source_dataset_id (required): Source dataset ID
output_dataset_id (required): Output dataset ID
dissolve_mode (optional): "all", "field", or "custom" (default: "field")
dissolve_field (required if mode="field"): Field to dissolve on
custom_field (required if mode="custom"): Field for custom grouping
custom_groups (required if mode="custom"): Array of group definitions
aggregation_fields (optional): Object mapping field names to aggregation functions (sum, avg, min, max, count)

Output

Creates a new dataset with dissolved features:

Merged geometries for each group
Aggregated attribute values
Group identifiers

Dissolve Modes

All Features

Merge all features into a single feature. No grouping field required.

By Field

Merge features that share the same value in the specified field.

Custom Groups

Merge features based on custom group definitions. Allows complex grouping logic.

Aggregation Functions

sum: Sum of numeric values
avg: Average of numeric values
min: Minimum value
max: Maximum value
count: Count of features

Example

# Enqueue a dissolve job via API
curl -X POST "https://example.com/api/run_dissolve.php" \
  -H "Content-Type: application/json" \
  -d '{
    "source_dataset_id": 123,
    "output_dataset_id": 124,
    "dissolve_mode": "field",
    "dissolve_field": "category",
    "aggregation_fields": {
      "population": "sum",
      "area": "sum"
    }
  }'

Background Jobs

This analysis runs as a background job. The worker:

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

Performance Considerations

Processing time depends on dataset size and number of groups
Complex geometries may slow processing
Aggregation operations add processing time
Consider simplifying geometries before dissolving

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