OCHA Centre for Humanitarian Data

Geospatial Impact Estimates

After a sudden-onset disaster, several agencies publish rapid satellite estimates of what has been damaged — and they disagree. This work builds those estimates, and measures how far they can be trusted before they inform a response.

Analysis & tools

Central Himalaya — experimental facet watch analyses

2,576 computed steep-glacier faces across the central Himalaya (82–89°E), colored by their 2026-season morning-radar anomaly ranked against 2020–25 history, with the validated detector run on the worst-ranked faces. Built by GEE batch export; a rank against the past, not a prediction.

/himalaya-facet-watch/

Langtang facet watch — live status map

580 computed steep-glacier faces in the Langtang region, each colored by its recent morning-radar anomaly ranked against 2020–25 history. Snapshot dashboard built on the SAR precursor analysis; a rank against the past, not a prediction.

/langtang-facet-watch/

Nepal glacier collapse — SAR precursor analysis

Six years of Sentinel-1 radar over the Langtang Lirung face that collapsed on 26 Aug 2026: a morning-pass melt anomaly visible four months out, a 45-face false-alarm test, and an offset-tracking null. One page, plain-language walkthrough with expandable technical panels.

/langtang-sar-precursors/

Analysis of EQ Damage Products: Presentation to A&A Cell 11 Aug 2026

Satellite building-damage products from the M7.5 Venezuela earthquake, evaluated against expert references: what arrived, what the products can and cannot support, and what actually works.

/slides/aa-cell-briefing-public/

Damage evaluation — A&A Cell briefingPassphrase

Five-slide briefing for the A&A Cell, 11 August 2026: the headline results of the damage product evaluation, with the full deck as backup slides.

/slides/aa-cell-briefing/

Damage evaluation — full results deckPassphrase

Six rapid building-damage products released after the M7.5 Venezuela earthquake, scored against three reference datasets chosen for their non-overlapping blind spots. The complete results deck.

/slides/damage-evaluation/

Damage evaluation — technical briefPassphrase

The condensed companion to the write-up: the three questions a coordinator would ask, answered with the headline figures, plus the full method appendix.

/brief/

Damage evaluation — technical write-upPassphrase

The manuscript behind the deck: matching basis, per-product scores, and the negative results that shaped the method.

/manuscript/

Vantor Open Data activation tracker

Which disasters Vantor (formerly Maxar) has released open imagery for, and how many pre- and post-event images each activation has. Rebuilt daily from the public STAC catalog, with a live-drift check on every page load.

/vantor-activations/

Damage exposure viewer — multi-eventExternal

The multi-event viewer: satellite building-damage sources compared on one exposure base, with coverage-aware admin aggregation and spreadsheet export. Currently the Venezuela (M7.5) and Colombia (M7.4) earthquakes.

azurestaticapps.net ↗

Geospatial impact viewer (legacy)External

The original single-event (Venezuela) viewer on Azure App Service — superseded by the multi-event viewer above; retained during the transition.

azurewebsites.net ↗

Scope. The paper artefacts are a single-event case study, frozen to the 2026-07-15 data snapshot. They report how these products performed on one earthquake; they are not a general verdict on any of them.

Access. The artefacts are pre-publication. Most open with a shared passphrase and are stored encrypted, so this repository being public does not expose them — but a passphrase is only as private as the people holding it.

Adding a page? Create a directory under pages/ with an index.html and add a card above. See pages/README.md.