TIFF, GeoTIFF, and Cloud Optimized GeoTIFF (COG) are three Raster file specifications.
At it’s simplest:
 | A Tiff file contains only an image. |
 | A GeoTiff contains both an image and location data. |
 | A COG is a GeoTIFF that has been modified to serve only those parts of the GeoTIFF required by an HTTP Get request. |
The ability of a COG to serve only those parts of a GeoTIFF requested, and not the entire GeoTIFF, make a COG more efficient and faster than a GeoTIFF.
A good analogy to distinguish a GeoTIFF from a COG is viewing a movie on DVD versus viewing a movie on a Streaming Service.
With a DVD, you take delivery of the entire DVD and then proceed to view it. A COG, conversely, only “streams” the bit you are actually watching at this moment.
A Cloud Optimized GeoTIFF accomplishes this in two way:
- By storing the image pixels in smaller untis
- By providing only the required units in response to an HTTP Get request.
You can convert your GeoTIFF to Cloud Optimized GeoTIFF using GDAL.
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