Frequently Asked Questions

Off-Nadir Delta is an AI-ready OSINT and satellite GEOINT platform that decides what is worth observing. Disasters, conflict, environmental change, and infrastructure failures unfold worldwide every day, but the signals are scattered across news, open data, and satellite imagery — and reading them takes expertise and time. Off-Nadir Delta combines an AI analyst, maps, satellite data, and open sources to explore, visualize, and prioritize geographic events, and to answer the questions that precede any imagery spend: can a satellite settle this, is free Sentinel-class data enough or does it need commercial tasking, and when can the place next be imaged. Factual claims link to their sources, judgments are labelled as judgments rather than facts, and each brief reports its own citation coverage — naming any claim that lacks a source — instead of producing an assessment anyway. There are three ways to look, distinguished by scope: Delta Watchfloor (everywhere, today — today's prioritized picture of global risk, so you know where to look now; the latest events up to the previous day are free to browse, and the real-time view of today is on paid plans), Delta Map (one place, right now — verify an event from space with Sentinel-1 C-band SAR, NISAR L-band SAR, Sentinel-2 optical, VIIRS nighttime lights, and NASA FIRMS active fires, no GIS software required), and Delta Watchlist (what you care about, over time — fix an area or follow an event, pick what to count such as ships alongside a berth, a burn index or a water index, and every new Sentinel-1, Sentinel-2, NISAR or VIIRS acquisition over it is measured automatically, with unusual readings flagged against the history). And two ways to be told: Delta Agent (an AI analyst that explains what happened and why it matters, and recommends which satellite sensor and area to image next) and Delta Reports (a written daily assessment with Key Judgments, calibrated confidence, and an outlook). Built for OSINT, geopolitical-risk, and satellite-intelligence analysts, and for developers integrating live signals and briefs through the API and MCP. Also applicable to emergency management, media, enterprise-risk, and research workflows. No intelligence background required. Free tier available.

Start on the Watchfloor to see where activity is concentrated today — geolocated conflict, security, disaster and infrastructure events, continuously refreshed, each with a severity score (ranked by imaging value on plans that include it). Then ask Delta Agent why a given event matters; it reasons over the live signals with real intelligence tradecraft and returns a sourced brief that recommends which satellite sensor and area to image — Sentinel-1 SAR for cloud, night, or vessel detection, Sentinel-2 optical for a visual look. Open the recommended scene on the Map to look closer. This "tip-and-cue" workflow takes you from the day's events to the right satellite image without switching tools.

No, Off-Nadir Delta is designed for beginners who have never used satellite data before. The intuitive interface lets you explore satellite imagery by simply navigating the map, selecting dates, and adding layers. You can learn by exploring — no technical background required.

Create a free account, navigate to the map interface, and use the Satellite Images panel to search for imagery over your area of interest. Select a date range, choose a satellite (Sentinel-1 or Sentinel-2), and add the imagery to your map. It takes just a few clicks to see satellite data.

Off-Nadir Delta works on all modern browsers including Google Chrome, Mozilla Firefox, Microsoft Edge, and Safari. For the best experience, we recommend using the latest version of Chrome or Firefox.

Yes, Off-Nadir Delta is responsive and works on tablets and smartphones. However, for the best experience with detailed satellite imagery analysis, we recommend using a desktop or laptop computer with a larger screen.

Delta Watchfloor is your daily global situational picture: near-real-time geolocated events (Delta Signals) on one map, with a timeline and a filterable list. Each event shows how precisely its place is known (reported, localized or pinpointed), whether a satellite could see it, its severity, how many outlets are reporting it, and the latest article from each outlet; plans that include them add the reported facts, every source with the report behind each fact, and what imagery would help. Without an account you can see the previous day’s top events and every event of that day on the map; a free account opens every event and its details. Add events or areas to your Watchlist to keep following them.

Delta Signals is a feed of geolocated conflict, security, disaster and infrastructure events, AI-enriched and continuously refreshed. It maps real-world events so you can overlay them on the areas you monitor and see what is happening on the ground. Event signals are distilled from global news media and official hazard feeds (significant earthquakes from the USGS and volcanic-ash advisories). Each signal links the latest article from each outlet that carried it and a location resolved only as far as the reporting names the place, so you can check the evidence behind it. Browsing the feed is free.

Yes. Every signal links the latest article from each outlet that carried it, so you can open the source and read it yourself; plans that include source detail show every article and the report behind each reported fact. When many outlets report the same event, they are folded into one signal, so the feed reflects real-world events rather than the volume of coverage — the outlet count is breadth of reporting, not independent confirmation, because syndicated reprints are not collapsed. Each event's location is taken from the places the reporting names, resolved only as far as they allow (reported, localized or pinpointed), and a coordinate that contradicts the reported country is dropped rather than drawn. The satellite-collection recommendation is only computed for events with clear geospatial relevance or reporting from several outlets. In short, every signal can be opened, checked, and shared.

Delta Agent is an AI intelligence analyst you chat with in plain language. It reasons over live Delta Signals with real GEOINT/OSINT tradecraft and returns a sourced, geolocated brief — recommending which sensor (SAR or optical) and which area to image next. It reads satellite imagery of the area, remembers the conversation for follow-ups, shows its sources, and hands every finding off to the map. This "tip-and-cue" workflow connects news to satellite imagery collection. Delta Agent is available to any registered user — each question draws from your token balance, so you only pay for the depth you use.

Delta Signals is built from global news media and official hazard feeds — significant earthquakes from the U.S. Geological Survey and volcanic-ash advisories (SIGMETs). Off-Nadir Delta adds AI enrichment on top: what happened, where, and whether a satellite could see it. All signals retain their source attribution, credited wherever signal data is shown.

Browsing the Delta Watchfloor is free. Without an account you see the previous day’s top events in the list and every event of that day on the map; a free account opens every event of the last three days and the free part of each event’s detail. Paid plans add the depth that professional workflows rely on: the real-time view of today (with the last 15 minutes and last hour filters), a date range to look back through — 30 days on Starter — what happened in each event (the reported facts, the places named and every change); Pro adds the evidence behind it: every source with the report behind each fact, the related events, the collection recommendation with the GEOINT score, and the market reasoning. Running AI remote-sensing deep-dives (Assess) is available to any signed-in account and is paid for with tokens. See the pricing page for current plan details.

You can access Sentinel-1 C-Band SAR, NISAR L-Band SAR, Sentinel-2 Optical, VIIRS Nighttime Lights (NASA Black Marble), and NASA FIRMS Active Fire hotspots. Sentinel-1 radar works through clouds day or night. NISAR adds L-band radar, whose longer wavelength penetrates vegetation canopy that C-band only sees the top of; its public collection is provisionally calibrated. Sentinel-2 provides 10m resolution multispectral imagery. VIIRS shows nighttime artificial lighting patterns. FIRMS provides near real-time fire detection at 375m (VIIRS) and 1km (MODIS) resolution.

VIIRS (Visible Infrared Imaging Radiometer Suite) Nighttime Lights, also known as NASA Black Marble, captures artificial light emissions from Earth at night. The daily product served is VJ146A2 from VIIRS on NOAA-20 (from 2019-08-28; earlier dates use the Suomi NPP archive product VNP46A2), providing daily cloud-free composite imagery at approximately 500-meter resolution. It is valuable for monitoring urban electrification, assessing disaster impacts on power infrastructure, and analyzing economic activity patterns.

NASA FIRMS (Fire Information for Resource Management System) provides near real-time active fire hotspot data detected by thermal sensors on satellites. VIIRS sensors detect fires at 375m resolution from NOAA-20 (the default here) and NOAA-21, with S-NPP selectable for dates up to October 31, 2026, as NOAA ends S-NPP data distribution on November 1, 2026; NASA states that near real-time detections are made available within about 3 hours of a satellite observation. MODIS provides 1km resolution detections from Terra and Aqua satellites with records dating back to 2000; the MODIS layer here runs roughly two days behind. Off-Nadir Delta displays this data via NASA GIBS WMS, so no API key is needed and viewing it costs no tokens. Which plans include the active-fires layer in the map workspace is listed on the pricing page.

No. NASA FIRMS active fire data is displayed in Off-Nadir Delta via NASA GIBS (Global Imagery Browse Services) WMS, which is freely accessible without any API key, account registration, or authentication. Fire data also does not consume any of your tokens. Whether the active-fires layer is available inside the map workspace depends on your plan — see the pricing page for what each plan includes.

Each fire detection from FIRMS is assigned a confidence level. High (red dots) represents the most reliable detections with strong thermal anomaly. Nominal (orange) represents standard-confidence detections. Low (yellow) represents possible fires with lower certainty. For monitoring active wildfires, focus on High and Nominal confidence detections.

Sentinel-1 and Sentinel-2 satellites revisit the same location every 5-6 days on average. VIIRS Nighttime Lights provides daily composite imagery. Actual availability depends on your location and satellite orbit. When you search, you will see all available dates for your area.

Sentinel-2 optical imagery has 10-meter resolution for visible and near-infrared bands. Sentinel-1 SAR imagery has 10-20 meter resolution. NISAR L-band GCOV is delivered on a 10-meter grid. VIIRS Nighttime Lights has approximately 500-meter resolution. NASA FIRMS Active Fire data has 375m resolution (VIIRS) and 1km (MODIS). These resolutions are suitable for monitoring land use changes, vegetation health, urban development, lighting patterns, and fire activity.

GRD (Ground Range Detected) is the standard Sentinel-1 product with basic processing. RTC (Radiometric Terrain Corrected) products are further processed to correct for terrain-induced distortions using a Digital Elevation Model, providing more accurate backscatter values especially in mountainous areas. Off-Nadir Delta provides access to RTC-corrected Sentinel-1 products.

SAR is a type of radar imaging that actively sends microwave signals and measures the reflected energy. Unlike optical sensors that rely on sunlight, SAR can capture images day or night and through cloud cover. This makes it invaluable for monitoring areas with frequent cloud coverage or for emergency response situations.

C-Band SAR (Sentinel-1, 5.6cm wavelength) is sensitive to surface features and small vegetation like leaves and branches. L-Band SAR (e.g., ALOS PALSAR, ~24cm wavelength) penetrates deeper into forest canopy, reaching tree trunks and the ground. L-Band is ideal for biomass estimation, deforestation detection, and wetland mapping, while C-Band excels at flood detection and surface change monitoring. Off-Nadir Delta provides C-Band SAR via Sentinel-1 and L-Band SAR via NISAR (NASA/ISRO). The public NISAR collection is provisionally calibrated, so its backscatter values should be read as indicative rather than measured.

VV (Vertical-Vertical) means the radar transmits and receives vertically polarized waves. VH (Vertical-Horizontal) means it transmits vertical and receives horizontal polarization. VV is more sensitive to surface roughness and soil moisture, while VH (cross-polarization) is useful for vegetation analysis and flood mapping since water has very low VH return.

Water surfaces appear very dark in SAR imagery because they reflect radar signals away from the sensor (specular reflection). Compare pre-flood and post-flood SAR images to identify newly flooded areas. VH polarization is particularly effective as flooded vegetation shows dramatically reduced backscatter. SAR can detect floods even through clouds.

Yes, ships appear as bright spots in SAR imagery due to their metal hulls causing strong radar reflection. The surrounding water appears dark, creating high contrast. Ship detection works day or night and through clouds. Off-Nadir Delta is useful for maritime monitoring: it detects vessels present in a scene, rather than identifying or tracking a named ship between scenes.

Speckle is a granular noise pattern inherent to SAR imagery caused by coherent interference of radar waves. It appears as a salt-and-pepper texture. Multi-looking (averaging multiple observations) reduces speckle but decreases resolution. The RTC products available in Off-Nadir Delta include multi-looking for reduced noise.

NDVI (Normalized Difference Vegetation Index) measures vegetation health using the formula (NIR - Red) / (NIR + Red). Values range from -1 to +1. Healthy vegetation shows values of 0.3-0.8, water is typically negative, and bare soil is near 0. In Off-Nadir Delta, select the NDVI visualization option when viewing Sentinel-2 imagery to see vegetation health.

Off-Nadir Delta supports multiple spectral indices including NDVI (vegetation health), EVI (Enhanced Vegetation Index for high-biomass areas), NDWI (water content), MNDWI, NDSI and NBR, alongside true color and false color composites. Select different visualization options in the layer settings to apply these indices.

Compare satellite imagery from different dates to detect forest cover changes. Use NDVI to highlight vegetation differences, or compare Sentinel-1 SAR backscatter changes, which are sensitive to canopy structure and work through clouds. Create time-series comparisons to track gradual deforestation over months or years.

False color composites display non-visible spectral bands (like near-infrared) as visible colors. The common NIR-Red-Green combination shows healthy vegetation as bright red, making it easy to distinguish vegetation types and identify stressed plants. In Off-Nadir Delta, select False Color visualization when viewing Sentinel-2 imagery.

Yes, Off-Nadir Delta is excellent for rapid disaster assessment. You can quickly view before-and-after imagery to assess flood extent, wildfire damage, earthquake impacts, and other natural disasters. NASA FIRMS Active Fire data provides near real-time wildfire hotspot detection. SAR imagery is particularly useful as it can capture images through smoke and clouds. Combine FIRMS fire hotspots with Sentinel-2 NBR for burn severity analysis.

Absolutely. With access to years of satellite archive data, you can compare imagery from different dates to track deforestation, urban expansion, coastline changes, glacier retreat, and seasonal vegetation patterns. The time-series analysis capabilities make it easy to visualize change.

Yes, Sentinel-2 imagery is widely used for agricultural applications. You can monitor crop health using vegetation indices, detect irrigation patterns, identify stressed crops, and track seasonal growing cycles. The regular revisit frequency allows you to follow crop development throughout the season.

Yes, VIIRS Nighttime Lights data correlates with economic activity and electrification. You can monitor urban growth over time, detect power outages after disasters, compare regional development levels, and analyze seasonal economic patterns. The data is updated daily and provides global coverage.

Tokens are deducted by operation. Tile requests, imagery searches, assessments, monitoring runs, and Analyst questions have different costs. Estimated and maximum costs are shown before execution. A map tile is metered by its pixels, band count, and processing type, so panning at a high zoom over a large area costs more than a single view. Your balance is displayed in the interface, and you can purchase additional tokens as needed. The token guide lists the per-action cost of every metered operation.

Yes, new users receive free tokens to explore the platform and understand its capabilities. The free tier provides enough tokens to evaluate whether Off-Nadir Delta meets your needs before committing to a paid plan. No credit card is required to get started.

When your token balance is depleted, you will not be able to load new satellite imagery tiles. Previously loaded imagery remains visible. You can purchase additional tokens through the Billing page to continue using the service.

Your monthly plan allocation resets at the start of each billing cycle — unused monthly tokens do not roll over. Tokens from one-time packages (available on paid plans) are separate: they never reset monthly and stay valid for 365 days from purchase. Check your Billing page to see your current token balance and reset date.

Off-Nadir Delta is built on open geospatial standards. It uses STAC (SpatioTemporal Asset Catalog) for satellite data discovery and Cloud Optimized GeoTIFF (COG) for efficient, on-demand imagery streaming — so you can view exactly the area you need without downloading entire scenes. Imagery comes from public missions including ESA Copernicus Sentinel-1 (C-band SAR) and Sentinel-2 (optical), the NASA-ISRO NISAR mission (L-band SAR), NASA VIIRS nighttime lights, and NASA FIRMS active fires. No GIS software or installation is required.

STAC is an open specification for describing geospatial data assets, enabling standardized search and discovery of satellite imagery. It provides a common language for metadata including spatial extent, temporal coverage, and available assets. Off-Nadir Delta uses STAC to search and access satellite imagery from public providers.

COG is a GeoTIFF file format optimized for cloud-based access. It uses internal tiling and overviews to allow efficient partial reads over HTTP. This means you can view just the portion of the image you need without downloading the entire file. Off-Nadir Delta streams COG data directly from cloud storage for fast visualization.

Yes, Off-Nadir Delta supports uploading GeoTIFF, Cloud Optimized GeoTIFF (COG), and GeoJSON files. You can overlay your own raster and vector data on satellite imagery for custom analysis. Uploaded data is displayed as layers that can be combined with satellite imagery.

Export and download capabilities are available on select plans. You can export layers as GeoJSON for vector data. For satellite imagery, the platform streams data directly from cloud sources to optimize performance and reduce storage requirements.

Yes, Off-Nadir Delta uses industry-standard security practices including encrypted connections (HTTPS), secure authentication, and data protection measures. Your account information and any custom layers you create are stored securely.