Off-Nadir Delta WebGIS
Off-Nadir Delta is a web-based satellite imagery workspace for anyone who is curious about satellite data — especially if you have never used it before and just want to see your area from space in a clear, simple way.
From there, you can slowly discover what is possible: quickly check a location after an event, watch how places change over time, and build maps you can share with others — all in your browser, without GIS software.
Get Started Without GIS Skills
Open the map in your browser, choose a place you care about, and see satellite imagery in seconds. No prior experience or special tools required.
Learn by Exploring
Try different views and dates to understand what you are seeing. Notice how water, vegetation, and cities appear in satellite images just by looking and comparing.
Speed Up Your Daily Checks
If you already work with satellite data, use Off-Nadir Delta to do quick visual checks and change detection before you dive into heavier tools and scripts.
Create a free account to explore your own locations and gently learn how satellite imagery can support your work and ideas.
Supported Satellite Data
Sentinel-1 (SAR)
Synthetic Aperture Radar imagery that works day and night, through clouds and smoke. Ideal for flood mapping, disaster response, and all-weather monitoring.
- • Ground Range Detected (GRD)
- • Radiometric Terrain Corrected (RTC)
- • Resolution: ~10-20 meters
- • Revisit: 6 days
Sentinel-2 (Optical)
Multispectral optical imagery with 13 spectral bands. Perfect for vegetation analysis, land cover mapping, and environmental monitoring.
- • Level-2A (atmospherically corrected)
- • Resolution: 10 meters (visible/NIR)
- • Revisit: 5 days
- • 13 spectral bands
Technology Stack
Map Visualization
Data Discovery
Cloud Optimized GeoTIFF
Web Framework
Built with modern geospatial standards: SpatioTemporal Asset Catalog (STAC) for data discovery and Cloud Optimized GeoTIFF (COG) for efficient streaming of satellite imagery.
Data Sources
Off-Nadir Delta provides access to satellite data from trusted, authoritative sources:
Copernicus Programme (ESA)
European Space Agency's Earth observation programme providing free and open Sentinel satellite data.
AWS Earth Search
Amazon Web Services hosting of Sentinel-2 data for fast, reliable access.
Microsoft Planetary Computer
Sentinel-1 RTC data processed and hosted by Microsoft for radiometrically corrected SAR imagery.
Open Data Policy
All Sentinel data is freely available under the Copernicus open data policy.