Category: Formats and access

COG (Cloud Optimized GeoTIFF)

A COG is a GeoTIFF organized for fast partial reads over HTTP, enabling streaming access without downloading the full file.

Also known as: Cloud Optimized GeoTIFF, cloud-optimized geotiff

Expanded definition

Cloud Optimized GeoTIFFs are structured with internal tiling and overviews so clients can request only the bytes they need using HTTP range requests.

This makes map previews and scalable analytics faster because you can read a small window, a lower-resolution overview, or a subset of bands without transferring the entire dataset.

COG is a packaging strategy, not a different data model. A COG can still have wrong CRS, bad nodata handling, or confusing scale factors if the underlying data is not documented well.

Related terms

GeoTIFF

GeoTIFF is a raster image format that embeds georeferencing metadata so pixels map to real-world coordinates.

Raster

A raster is a grid of pixels where each pixel stores a value, commonly used for satellite imagery and elevation models.