Image
What is a .cog file?
A .cog file is a Geographic Tagged Image File Format (GeoTIFF). This is an image format — a picture, drawing or graphic.
How to open a .cog file
- GIMP (free) and IrfanView open a very wide range of image formats, including obsolete ones.
- XnView MP is the best bet for unusual or legacy image types.
- Your operating system's built-in viewer may work for mainstream formats.
The registry records this extension against Geographic Tagged Image File Format (GeoTIFF), so software from that family is the most likely match.
How to convert a .cog file
- Open it in GIMP or XnView and export as .png (lossless) or .jpg (smaller).
MIME type
When a .cog file travels over the web, servers label it with this MIME type:
image/tiffThe technical record
For archivists, developers and the merely curious: these are the PRONOM registry entries for .cog.
| Format name | Version | MIME type | PUID |
|---|---|---|---|
| Geographic Tagged Image File Format (GeoTIFF) | — | image/tiff | fmt/155 |