If you work with maps, you have opened a GeoTIFF — probably without realizing it. It is the standard way geospatial imagery is stored and shared.

A GeoTIFF is an ordinary TIFF image file with extra tags embedded in it that describe where the image sits on the Earth: its coordinate system, its projection, the size of each pixel, and the location of its corner.

Georeferencing is what turns a picture into data. Without location tags, an aerial photo is just a grid of pixels; with them, every pixel has coordinates, so you can measure distances and overlay the image on other maps.

Not all GeoTIFFs are built the same. A cloud-optimized GeoTIFF arranges data in internal tiles so software can fetch just the part you are viewing. Some are compressed, and some store elevation data instead of imagery.

Working with GeoTIFFs in QGIS is straightforward: drag the file into the map, and it appears in the right place if the tags are correct. To create one, export any raster layer and choose GeoTIFF as the format.

GeoTIFF is not always the right choice — for vector data it is the wrong tool entirely. But for imagery, elevation, and raster analysis, it remains the default because it is open, widely supported, and self-describing.