Satellite Data Sources
Every data source behind the Map, the Watchfloor, and Delta Agent — what it is, how sharp it is, how often it refreshes, and how to credit it. All open data, all in your browser.
TL;DR: Off-Nadir Delta provides Sentinel-2 optical (10 m, 13 bands), Sentinel-1 C-band SAR (10 m, VV/VH), OPERA RTC-S1 terrain-corrected SAR (Sentinel-1 derived), VIIRS nighttime lights (NASA Black Marble, ~500 m), and NASA FIRMS active fire (375 m, daily). You can also upload your own GeoTIFF, COG, or GeoJSON data.
Sentinel-2 Optical
OpticalESA Copernicus Programme
High-resolution multispectral optical imagery. Thirteen spectral bands from visible through near-infrared and shortwave infrared make it the workhorse for vegetation, land cover, and water analysis.
Resolution
10 m (visible/NIR)
Bands
13 spectral bands
Revisit
~5 days (constellation)
Level
L2A surface reflectance
Typical uses: True color and false color composites, NDVI / EVI / NDWI vegetation and water indices, crop and forest monitoring, land-cover change.
Attribution: Contains modified Copernicus Sentinel data [year]
Open Sentinel-2 ViewerSentinel-1 C-Band SAR
RadarESA Copernicus Programme
C-band Synthetic Aperture Radar that images the surface day or night and sees straight through cloud, smoke, and light rain. Delivered as GRD products in VV and VH polarizations.
Resolution
~10 m (IW mode)
Polarization
VV, VH
Revisit
6-day repeat cycle
Frequency
C-band, 5.405 GHz
Typical uses: Flood mapping, surface-change detection, vessel detection, and all-weather monitoring where optical imagery is blocked by clouds.
Attribution: Contains modified Copernicus Sentinel data [year]
Open Sentinel-1 SAR ViewerOPERA RTC-S1
Analysis-Ready SARNASA JPL via Alaska Satellite Facility (ASF)
Analysis-ready, Radiometrically Terrain Corrected backscatter derived from Sentinel-1 (C-band). Terrain correction with a DEM makes backscatter values comparable across slopes — ideal for quantitative and time-series work in hilly terrain.
Source
Sentinel-1 (C-band)
Processing
Radiometric Terrain Correction
Format
Cloud-Optimized GeoTIFF
Distributor
ASF DAAC
Typical uses: Time-series backscatter comparison, terrain-aware change detection, and SAR analysis where consistent radiometry matters.
Attribution: OPERA RTC courtesy NASA/JPL-Caltech
Explore SAR imageryVIIRS Nighttime Lights
NighttimeNASA Black Marble (VNP46A2)
The VIIRS Day/Night Band measures visible light at night. NASA Black Marble products are calibrated and atmospherically corrected, turning city lights into a proxy for human activity.
Resolution
~500 m
Product
Black Marble VNP46A2
Revisit
Daily
Sensor
VIIRS Day/Night Band
Typical uses: Tracking urban development and electrification, estimating economic activity, and detecting power outages after disasters.
Attribution: NASA Black Marble VNP46A2
Open Nighttime LightsNASA FIRMS Active Fire
Active FireNASA FIRMS
Near real-time thermal fire detections from VIIRS and MODIS. Hotspots are updated daily and overlaid directly on the map — no account or API key required to browse.
Resolution
375 m (VIIRS), 1 km (MODIS)
Latency
Near real-time, daily
Sensors
VIIRS, MODIS thermal
Cost
Free to browse
Typical uses: Wildfire situational awareness, monitoring fire spread, and correlating thermal anomalies with events on the Watchfloor.
Attribution: NASA FIRMS
Open Active Fire MapYour Own Data
Bring Your OwnUploaded by you
Bring GeoTIFF, Cloud-Optimized GeoTIFF, or GeoJSON files and combine them with satellite imagery on a single map. Your data stays alongside the open sources for custom analysis.
Raster
GeoTIFF, COG
Vector
GeoJSON
Use
Overlay with satellite layers
Reference
OpenStreetMap basemaps
Typical uses: Overlaying field boundaries, custom AOIs, survey results, or third-party rasters together with Sentinel and VIIRS imagery.
Attribution: You retain ownership of uploaded data
Upload Your DataAttribution & Licensing
All satellite sources come from free and open programmes. When you export or publish imagery, include the relevant attribution below.
Sentinel-1 & Sentinel-2
European Space Agency (ESA) Copernicus Programme
"Contains modified Copernicus Sentinel data [year]"
VIIRS Nighttime Lights
NASA Black Marble (VNP46A2)
"NASA Black Marble VNP46A2"
OPERA RTC-S1
NASA JPL via Alaska Satellite Facility
"OPERA RTC courtesy NASA/JPL-Caltech"
NASA FIRMS Active Fire
NASA Fire Information for Resource Management System
"NASA FIRMS"
Reference Layers
OpenStreetMap contributors
"© OpenStreetMap contributors"
Your Own Data
Uploaded GeoTIFF / COG / GeoJSON
You retain ownership of uploaded data
Frequently Asked Questions
Is the satellite data free?▼
What is the difference between Sentinel-1 and Sentinel-2?▼
Is OPERA RTC-S1 the same as NISAR L-band SAR?▼
How often is each source updated?▼
Do I need to credit the data sources?▼
Can I add my own data?▼
Start Exploring These Sources
Open Sentinel-1, Sentinel-2, OPERA RTC-S1, VIIRS, and NASA FIRMS data with a free account.