Off-Nadir Delta

fundamentals

19 articles

What Can You Actually See in 10 m Satellite Imagery? An OSINT Guide by Target

What free 10 m Sentinel-2 and Sentinel-1 imagery can and cannot show for the things OSINT analysts ask about: vehicles, buildings, ships, airfields, fires, floods and earthworks.

2026-10-04 · 7 min read

How Accurate Is Satellite Data? A Practical Guide to Validation and Uncertainty

Satellite measurements are estimates, not ground truth. Learn the accuracy metrics that matter — RMSE, MAE, bias, R², confusion matrices, and cloud confidence — how to validate results, and how to communicate uncertainty honestly in any remote sensing analysis.

2026-06-21 · 5 min read

MODIS Satellite Data: The Daily, Decades-Long View of Earth

MODIS provides daily global coverage and a 20+ year archive at 250m-1km resolution. Learn what MODIS measures, its key products (NDVI, land surface temperature, active fire), how it trades resolution for frequency, and when coarse-resolution daily data beats high-resolution imagery.

2026-06-20 · 4 min read

Synthetic Aperture Radar (SAR): The Complete Guide

A complete, structured guide to Synthetic Aperture Radar (SAR) for Earth observation — how SAR works, why it sees through clouds, polarization, backscatter, InSAR, and the full range of applications from flood mapping to ship detection. Your hub for every SAR topic.

2026-06-19 · 5 min read

The Landsat Program: A Complete Guide to 50+ Years of Earth Observation

Landsat is the longest continuous record of Earth's surface from space, running since 1972. Learn how Landsat 8 and 9 work, what their OLI and TIRS sensors measure, how the 30m archive enables long-term change detection, and how Landsat compares to Sentinel-2.

2026-06-18 · 5 min read

SAR vs Optical Satellite Imagery: A Practical Guide to Choosing the Right Sensor

SAR and optical satellites measure fundamentally different things. This guide explains the physics, strengths, and limitations of each — and when to combine them for better results.

2026-02-10 · 6 min read

Orthorectification & Geometric Correction, Explained

What orthorectification and geometric correction do to satellite images, why terrain causes distortion, and how DEMs and ground control points fix it.

2026-02-06 · 7 min read

Supervised vs Unsupervised Classification in Remote Sensing

Supervised and unsupervised classification compared: inputs, algorithms (Random Forest, k-means), accuracy assessment and when to use each for land cover.

2025-12-07 · 7 min read

How Do Satellites Actually Capture Images? Pushbroom, Whiskbroom, and SAR

A behind-the-scenes look at how Earth observation satellites acquire images. Understand pushbroom scanning, whiskbroom sensors, SAR synthetic aperture techniques, and why it matters for your data.

2025-12-01 · 7 min read

Radiometric Calibration: From Digital Numbers to Physical Measurements

How satellite sensors convert raw digital numbers into meaningful reflectance or radiance values. Understand gain, offset, and why calibration is the first step in any serious analysis.

2025-11-21 · 7 min read

4 Types of Resolution in Remote Sensing, Explained

Spatial, spectral, temporal and radiometric resolution in remote sensing: what each means, typical values for common satellites, and the trade-offs.

2025-11-18 · 8 min read

Atmospheric Correction: Why Raw Satellite Images Need Processing

What atmospheric correction does, why it matters for satellite data analysis, and what happens if you skip it. A practical explanation of TOA reflectance, BOA reflectance, and when correction is critical.

2025-11-15 · 8 min read

Spatial vs Temporal Resolution: The Fundamental Trade-Off in Satellite Imaging

Why you can't have both high spatial and high temporal resolution from a single satellite. Understand the trade-off, how constellations address it, and how to choose the right balance for your project.

2025-11-05 · 7 min read

Satellite Orbit Types: SSO, Polar & GEO Explained

Sun-synchronous (SSO), polar and geostationary orbits explained: altitude, inclination and repeat cycle, with the orbits Sentinel-1/2 and Landsat fly.

2025-10-28 · 8 min read

Electromagnetic Spectrum in Remote Sensing: Bands & Uses

Visible, NIR, red edge, SWIR, thermal and microwave bands in remote sensing: wavelength ranges, what each band reveals, and why atmospheric windows matter.

2025-10-22 · 8 min read

What Is Remote Sensing? A Plain-Language Guide for 2025

Remote sensing explained without the jargon. Learn how satellites collect data about Earth, the difference between active and passive sensors, and where this technology is actually used today.

2025-10-15 · 9 min read

Reference Layers: Adding Geographic Context to Satellite Imagery

Satellite imagery alone doesn't tell the whole story. Basemaps, boundaries, and infrastructure layers provide the geographic context needed for meaningful interpretation. This guide covers how to use reference layers effectively.

2025-08-06 · 7 min read

Choosing the Right Colormap for Satellite Data Visualization

The colormap you choose changes what patterns you see in satellite data. This guide explains perceptual principles behind popular colormaps and when to use each one for different types of satellite imagery.

2025-07-20 · 7 min read

Understanding SAR Backscatter Coefficient (σ⁰): What the Numbers Actually Mean

A practical guide to interpreting SAR backscatter values. Learn what sigma-nought represents, why it's measured in decibels, typical values for different land cover types, and how to avoid common interpretation mistakes.

2025-06-06 · 7 min read