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27 guides on Raster.
What is Synthetic Aperture Radar (SAR)? Bands, Data, Uses
Synthetic aperture radar (SAR) images the ground with microwaves, day or night, through cloud. How SAR works, its bands, products, and data sources.
Raster vs. Vector Data: Differences, Formats, and Uses
Raster data is a grid of pixels. Vector data is points, lines, and polygons. How the two GIS data models differ, their formats, and how to combine them.
What is NDVI? Formula, Values, and Uses
NDVI, the normalized difference vegetation index, measures how green and dense vegetation is from red and near-infrared light. The formula, what the values mean, and how to calculate it.
What is Physical AI? Definition, Examples, How It Works
Physical AI is artificial intelligence that perceives, reasons about, and acts in the physical world: robots, autonomous vehicles, drones, world models, and Earth-scale models.
What is LiDAR Data? How It Works, Formats, and Sources
LiDAR (light detection and ranging) data is a set of 3D points measured by a laser scanner, which times each light pulse's round trip to a surface. Each point carries x, y, and z coordinates, the echo's strength (intensity), its order (return number), and a class code such as ground, vegetation, building, or water. Airborne […]
What is Landsat? Satellites, Bands, Data Access
Landsat is the joint U.S. Geological Survey (USGS) and NASA Earth observation program that has imaged the Earth's land surface continuously since July 1972. It is the longest record of its kind. Landsat 8 and 9 image every land pixel every 8 days, with 30 m color and infrared bands and 100 m thermal bands. […]
What is Hyperspectral Imaging? vs Multispectral
Hyperspectral imaging records a continuous spectrum for every pixel. A typical sensor records 200 to 450 narrow bands, each 5 to 10 nanometers wide, across visible, near-infrared, and shortwave infrared light. Multispectral imagery records 3 to 15 broad bands. The narrow bands let analysts identify minerals, crops, and gases by their absorption features, the wavelengths […]
What is the HRRR Model? NOAA Rapid Refresh Forecast
The High-Resolution Rapid Refresh (HRRR) model is a numerical weather prediction (NWP) model from the National Oceanic and Atmospheric Administration (NOAA). It runs every hour on a 3 km grid over the contiguous United States, with an Alaska domain every three hours. Each run starts from the latest radar, satellite, aircraft, and surface observations and […]
What is a GeoTIFF? Format, Tags, and COG
A GeoTIFF is a TIFF (Tagged Image File Format) image file that carries georeferencing metadata in standardized tags, so each pixel maps to a coordinate on Earth. The tags record the coordinate reference system (CRS), the pixel size, and the position of the grid origin. A Cloud Optimized GeoTIFF (COG) arranges the same file so […]
What is Geospatial AI? GeoAI Models, Agents, Examples
Geospatial AI, also called GeoAI or spatial AI, is the use of machine learning and AI agents on data tied to places on Earth. That data includes satellite and aerial imagery, maps, elevation, parcels, and location records. It covers computer vision on imagery and foundation models that turn imagery into embeddings, reusable lists of numbers […]
What is a Flood Risk Map? Zones, Depth Grids, Data
A flood risk map shows where flooding is likely, how deep the water could get, and how often a flood of that size is expected. In the United States the regulatory flood risk map is the flood map of the Federal Emergency Management Agency (FEMA). It marks the Special Flood Hazard Area: land with a […]
What is Earth Observation Data? Types, Sources
Earth observation data is the imagery and measurements of the Earth's surface, oceans, and atmosphere collected by satellites, aircraft, and drones. It includes optical and radar imagery, elevation, land cover, sea surface temperature, and atmospheric gases, delivered as dated rasters: grids of pixels tied to map coordinates. Open programs such as Copernicus, NASA, and Landsat […]
