Initial public release

docs/CHANGE_DETECTION_SPEC.md

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+# GeoIntel Kempen — Change Detection Specification v1.0
+
+Change Detection is a major showcase workflow combining raster, vector, AI and QA/QC.
+
+## Goal
+
+Compare two datasets or analysis runs for the same area and detect additions, removals and significant changes.
+
+## Supported methods
+
+## Method A — Vector change detection V1
+
+Compare two vector layers or two analysis outputs.
+
+Examples:
+
+- GRB buildings snapshot A vs snapshot B.
+- AI detections from raster A vs AI detections from raster B.
+- OSM buildings from run A vs OSM buildings from run B.
+
+### Inputs
+
+- layer A
+- layer B
+- area polygon
+- class filter optional
+- matching threshold
+
+### Algorithm
+
+1. Normalize CRS.
+2. Clip both layers to area.
+3. Match features using IoU or spatial overlap.
+4. Classify:
+   - added: feature in B without match in A
+   - removed: feature in A without match in B
+   - unchanged: matched with stable geometry
+   - modified: matched but area or geometry changed above threshold
+
+### Metrics
+
+- added count
+- removed count
+- modified count
+- added area m²
+- removed area m²
+- net area change m²
+- percentage change
+
+## Method B — Raster index change V2
+
+Compare NDVI/NDWI/NDBI rasters.
+
+### Inputs
+
+- index raster A
+- index raster B
+- threshold
+
+### Algorithm
+
+```text
+delta = index_B - index_A
+classify pixels by threshold
+polygonize changed zones
+```
+
+### Outputs
+
+- change raster
+- changed polygons
+- summary statistics
+
+## Method C — AI segmentation change V3
+
+Run segmentation on both images and compare class polygons.
+
+Examples:
+
+- vegetation loss
+- new buildings
+- water change
+
+## Output layers
+
+- `change_added`
+- `change_removed`
+- `change_modified`
+- `change_heatmap`
+- `change_uncertain`
+
+## API
+
+```http
+POST /analysis/change-detection
+GET /analysis/{id}/changes
+POST /analysis/{id}/exports/change-geojson
+```
+
+## UI requirements
+
+Change Lab must support:
+
+- dataset/layer A selector
+- dataset/layer B selector
+- method selector
+- area selector
+- threshold controls
+- timeline labels
+- map overlays for added/removed/modified
+- metrics cards
+- export
+
+## V1 target
+
+Implement vector change detection. Raster and AI-based change detection are later phases.