swissEO Browser

Configuration:

Layers:

Not for operational use

This is an experimental beta prototype. It is not intended for operational use: values, renderings and statistics are computed in the browser, are not validated and may be wrong or incomplete. For authoritative data use the swisstopo products and services directly.

Layer verification: we will check every layer in depth: data access, scaling and no-data, formula, masks and rendering, compared with reference implementations (e.g. GDAL / rasterio reads and the original scripts). A layer that passed this check carries the symbol VER_OK Verified; all others show VER_TODO To be verified. The status is kept as a checklist in the README and applied to the website on every deployment.

The website was developed with the help of Claude Code (Anthropic), an AI coding assistant.

Selected date

No acquisition selected.

Scaling and no-data

Taken from the swisstopo Additional Content Information sheets (S2-SR v200, VHI, NDVIdiff, NDVIz). Physical value = DN × scale + offset.

Asset	Scale	Offset	No-data
B01–B12, B8A	0.0001	−0.1	0 (uint16)
AOT	0.001	0	0 (uint16)
SCL	1	0	0 (uint8)
Cloud mask	1	0	0 = clear · 1 thick · 2 thin · 3 shadow
Terrain mask	1	0	255 · 0–180° lit · 200 shadow
TCI	1	0	0 (uint8)
VHI (WMS)	n/a	n/a	110 = no data
VHI (COG)	1	0	255 · 0–100 VHI
NDVIdiff	0.001	0	32701 · 32700 missing
NDVIz	0.01	0	32701 · 32700 missing

How this works

Everything on screen comes from public swisstopo services. There is no other backend.

Basemaps: wmts.geo.admin.ch (pixelkarte-farbe, swissimage, pixelkarte-grau) on the native LV95 tile grid.

Label overlay: wmts.asit-asso.ch asitvd.fond_pourortho, published on the identical LV95 grid. It sits in its own pane above the data layers.

Dates: without a date in the link the latest date with data opens. The calendar and ‹ › only offer days whose acquisitions reach the map view: the data footprint of each relative orbit is read once from the coarsest B04 overview (the STAC geometry is only the rectangular extent). The calendar and the ‹ › buttons query the STAC API data.geo.admin.ch/api/stac/v0.9. Cloud cover is CLOUDPERCENTAGE from each mosaic's metadata.json (OmniCloudMask). When several orbits were acquired on the same day, all of them are mosaicked, most recent on top.

Spectral layers: the band COGs are read straight from data.geo.admin.ch over HTTP range requests (geotiff.js). Only the overview matching the zoom and the tiles in view are fetched.

Masks: Clouds hides cloud-mask codes 1 and 2, Cloud shadows code 3, and Terrain shadow terrain-mask value 200 (cast or self-shadow from swissSURFACE3D at acquisition time). The vegetation mask keeps forest or all vegetation, read from the forest-10m / vegetation-10m COGs of swissEO VHI v100 (inside = value ≠ 255).

VHI: wms.geo.admin.ch layers ch.swisstopo.swisseo_vhi_v100 and …_vegetation with the item= day selector. Titles and abstracts come from the WMS GetCapabilities document.

Area of interest: the pentagon button on the map draws a rectangle (axis-aligned in LV95) or polygon, or imports KML/KMZ, GPX, WKT, GeoJSON, zipped Shapefiles (from a file or a URL), an MGRS/GEOREF cell or a bounding box (WGS84, LV95, LV03). Limits: files up to 50 MB, areas up to 100,000 vertices. An area imported from a file is only part of a copied link when it is small (about 270 vertices); one loaded from a URL is shared as the URL. Vertices stay editable; drawing again adds a polygon. Statistical info reads the COGs over the area for the selected date (statistics, histogram) and over a date range (time series, CSV); swissEO VHI statistics come from the forest-10m / vegetation-10m COGs. The spectral explorer plots mean reflectance of all 12 bands. The image download can be clipped to the area.

Configurations: as the themes of the Copernicus Browser, a configuration lists the layers for a task: Default, Agriculture, Drought, Drought 2026 with highlights, and Forest. Each layer keeps its own data source and dates.

Forest Disturbance Classification: the Sentinel Hub custom script of Joanneum Research (EvoLand), run in the browser on swissEO S2-SR: the model expects Sentinel Hub DN as 10000 × reflectance, which is swissEO DN − 1000. Its 150 trees are loaded on first use from jsDelivr, pinned to a commit.

Coordinates: positions are given in LV95 (EPSG:2056) everywhere, also in the permalink (center=2703331.08,1133878.99, as on map.geo.admin.ch).

Custom mask: the fifth mask of every layer keeps the data inside (or, inverted, outside) your own polygons (e.g. a forest map), loaded from a file or URL like an area of interest (up to 50 MB and 1,000,000 vertices). It applies to the map, statistics, exports and the timelapse.

Highlights: click a story to open it on the map (the card turns blue; a split comparison of two dates, drag the handle); the chevron shows the text, whose last line opens the compare settings. Texts after watson.ch (10 August 2026) and SRF Meteo (9 July 2026), credited in each story.

NDDI: by default with the NIR/SWIR NDWI of Gu et al. (2007). The green/NIR NDWI of the openEO notebook is selectable, but saturates (99.8 % of the pixels at ±1 in a test, with or without the reflectance offset).

Loading: the box at the bottom left counts the tiles still rendering and the requests in flight, and flags a slow connection after 6 s.

NDVIdiff / NDVIz: monthly products for the end of July, August and September (forest perimeter); the product nearest to the selected date is shown, also in compare, timelapse and export. NDVIdiff v200 BETA (beta data, example COGs on cms.geo.admin.ch, not in STAC): the NDVI change of two-month first-quartile cloud-free mosaics (June/July, July/August, August/September) against the same window one year earlier.

Two-date layers: NDDI change and the NDVI Analyst compare the selected date with a reference: the acquisitions within ±20 days of the same day one year earlier (or of a chosen date), clearest first, per pixel the first clear one.

Permalink: the address bar is rewritten on every change (view, date, cloud filter, layer, legend range, masks, effects, compare list, area of interest), so copying the URL reproduces the view.

Projection: EPSG:2056 (CH1903+ / LV95), the native CRS of the tile grid and the COGs, so nothing is reprojected.

Based on and uses

eu-cdse/copernicus-browser: the Copernicus Browser, model for the user interface, themes, layer descriptions and previews
davidoesch/swisseobrowser: this website
swisstopo/topo-satromo-v2: processing of the swissEO products (S2-SR, VHI, NDVIdiff, NDVIz, vegetation masks)
swisstopo/topo-drought-briefing: colour scheme
RaffiBienz/ndvi_analyst: NDVI Analyst of the Canton of Aargau (method of the NDVI Analyst layer)
Open-EO/openeo-community-examples: NDDI drought notebook
sentinel-hub/custom-scripts: index definitions and visualisations
Leaflet, Proj4Leaflet, proj4js, Leaflet-Geoman: map
geotiff.js: reading the COGs
togeojson, shpjs, mgrs, JSZip, gifenc: import, export, timelapse

Image download

Import area of interest

Statistical info

Spectral explorer

Timelapse

Pixel