Sentinel-1 Change Detector¶

Candidate-first satellite change detection for Norwegian construction activity. This repository combines Sentinel-1 GRD intensity, optional Sentinel-1 coherence, optional Sentinel-2 optical indices, FKB-Tiltak/custom candidate polygons, and validation utilities for producing a GIS review queue — not an automatic building register.

Candidate workflow¶

recommended

Start from FKB-Tiltak or custom polygons, model a Sentinel-1 seasonal baseline, then flag durable construction-like increases.

Open workflow

BBox / pixel exploration¶

diagnostic

Scan small AOIs as rasters to inspect where the detector fires, then vectorize clusters for review.

Pixel guide

Validation & limits¶

read before use

Understand the small-building signal ceiling, base-rate false positives, and why coherence/S2 fusion helps.

Limits & validation

Best-supported operating mode

Use run_senbygg_improved.py with candidate polygons. It calls senbygg_improved.py, applies the validated improvements, and can OR-fuse Sentinel-1 intensity, coherence, and Sentinel-2 evidence into one GeoPackage review layer.

Scope

A flag means review this candidate first, not confirmed construction. Compare the output with orthophoto, FKB, permit status, Sentinel-2, coherence, and local knowledge.

What is in the codebase?¶

Path	Status	Purpose
`run_senbygg_improved.py` + `senbygg_improved.py`	Recommended	Candidate/polygon-first S1 detector with optional COH/S2 fusion.
`bbox_change_detector.py`	Diagnostic	Pixel-level bbox/vector AOI scan; writes GeoTIFF change maps.
`fkb_common.py`	Core library	openEO, NetCDF, raster/polygon extraction, seasonal models, raster outputs.
`senbygg_s2.py`, `senbygg_coh.py`	Fusion	Optional optical/coherence evidence for candidate polygons.
`fkb_tiltak_*`	Legacy/research	Earlier polygon-median and CUSUM variants.
`validation/`	Evidence	Hodlekve/Kvamskogen labels, experiments, metrics, sweeps.

AOI + time window -> FKB/custom candidates -> S1 yearly cubes
  -> seasonal baseline -> durable increase-only score
  -> optional COH/S2 confirmation -> GeoPackage review layer