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79 lines
2.1 KiB
Markdown
79 lines
2.1 KiB
Markdown
# Hot Spot Analysis
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Identify statistically significant clusters of high and low values using Getis-Ord Gi* statistics.
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## Overview
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Hot spot analysis uses the Getis-Ord Gi* statistic to identify statistically significant spatial clusters. Features are classified as:
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- **99% Hot Spot**: Very high values, 99% confidence
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- **95% Hot Spot**: High values, 95% confidence
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- **90% Hot Spot**: High values, 90% confidence
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- **Not Significant**: No significant clustering
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- **90% Cold Spot**: Low values, 90% confidence
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- **95% Cold Spot**: Low values, 95% confidence
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- **99% Cold Spot**: Very low values, 99% confidence
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## Inputs
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- **Dataset**: Point or polygon dataset
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- **Value Field**: Numeric field to analyze
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- **Neighbor Type**: Distance-based or K-nearest neighbors
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- **Distance** (if distance-based): Maximum neighbor distance
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- **K Neighbors** (if KNN): Number of nearest neighbors
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## Outputs
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New dataset containing:
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- Original geometry
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- **Gi* Z-Score**: Standardized z-score
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- **P-Value**: Statistical significance
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- **Hot Spot Class**: Categorized class
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- Original attributes
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## Algorithm
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1. Calculate spatial weights matrix based on neighbor configuration
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2. Compute Getis-Ord Gi* statistic for each feature
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3. Calculate z-scores and p-values
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4. Categorize into hot spot classes
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5. Store results in output dataset
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## Example
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```json
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{
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"dataset_id": 123,
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"value_field": "population",
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"neighbor_type": "distance",
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"distance": 1000
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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. See [Hot Spot Analysis Worker](../workers/hotspot_analysis.md) for details.
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## Use Cases
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- Crime analysis
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- Disease clustering
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- Economic activity patterns
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- Environmental monitoring
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- Social phenomena analysis
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## Notes
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- Requires numeric field with sufficient variation
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- Distance should be appropriate for data scale
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- KNN method is generally faster for large datasets
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- Results depend on neighbor configuration
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## Related Documentation
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- [Hot Spot Analysis Worker](../workers/hotspot_analysis.md)
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- [Analysis API](../api/analysis.md)
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- [Live Hot Spot Analysis](hotspot-live.md)
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