What Is a Cloud Optimized GeoTIFF (COG)?

An orthophoto from a drone flight can easily be gigabytes. The classic way to share it — download, open, inspect on a powerful machine — doesn't scale. Cloud Optimized GeoTIFF (COG) solves exactly that: huge orthophotos are read from the cloud piece by piece and open instantly in the browser.

The problem: regular GeoTIFF reads poorly from the cloud

A standard GeoTIFF is a TIFF with georeferencing; its internal layout, however, was not designed for partial reads over the network. Even if you only want to look at a small area on the map, the client usually has to download most of the file.

The solution: COG's internal layout

A COG is still a 100% valid GeoTIFF — the difference is organization:

• Tiling: the image is split into small tiles; only the tiles visible on screen are downloaded.
• Overviews: lower-resolution copies live in the same file; zooming out reads the small copy.
• HTTP range reads: the client requests only the byte ranges it needs.

The result: a 3 GB orthophoto appears the moment the map opens — because only a few hundred kilobytes of tiles have been fetched.

The COG workflow in CartaX

1. Upload a raw GeoTIFF (up to 3 GB / ~1.5 gigapixels): it is converted to COG in the cloud (uses processing tokens) and served to your map as tiles. Cloud COG conversion is Professional-plan only; on the Free plan this upload type is locked. CartaX Studio runs the same conversion on your own machine without spending tokens.
2. If your file is already a COG: it is auto-detected and registered token-free — usable immediately with no conversion wait. Within your storage quota you can upload much larger COGs. Detection requires the TIFF to be tiled and contain at least one overview. A tiled TIFF without overviews is treated as raw — the 3 GB cap, cloud conversion and tokens apply.

Add a DSM/DTM next to your orthophoto to enable elevation readouts, profiles and volume measurement — see DSM vs DTM.

How do I produce a COG myself?

Most photogrammetry suites can export COG directly. With GDAL it is a single command:

gdal_translate input.tif output-cog.tif -of COG -co COMPRESS=DEFLATE

CartaX Studio is the desktop companion that runs this conversion on your own machine and uploads the output straight to your account.

Summary

Question	Answer
Is a COG a valid GeoTIFF?	Yes — every COG is a GeoTIFF; the difference is internal layout
Why is it fast?	Tiling + overviews + HTTP range reads: only the visible part downloads
CartaX limits?	Raw TIFF 3 GB / ~1.5 GP (with conversion); ready COGs within your storage quota
Do I need tokens?	Yes for raw TIFF conversion (Professional plan only); no for registering a ready COG or converting locally in Studio
How is a ready COG detected?	Tiling + at least one overview; a TIFF without overviews counts as raw