GeoTIFF

GeoTIFF is a public domain metadata standard which allows georeferencing information to be embedded within a TIFF file.

The GeoTIFF format is commonly used to provide elevation raster data. High-accuracy, high spatial resolution (1 m or less) elevation data from LIDAR measurements is often provided in the GeoTIFF format.

Unlike SRTM, which uses a grid with rectangular bounds aligned with the latitude-longitude coordinate system and has strictly ordered tiles that connect to one another with tiles always overlapping by one edge row or column of data, GeoTIFF uses various reference coordinate systems which are to the discretion of the respective issuer. This means in practice that a GeoTIFF grid, if projected to the latitude-longitude coordinate system may have non-rectangular bounds and irregular grid spacing in this coordinate system. GeoTIFF grids obtained as individual files from the same source do also typically lack a contract whether and how they overlap. The advantage of elevation data obtained as GeoTIFF is that it is often available as highly accurate high-resolution (1 m or less) data, whereas even the higher resolution SRTM1 has a grid spacing of circa 30 m (with the actual values in both grid dimensions depending on the latitude and longitude location).

When working with GeoTIFFs, the open source GeoTIFF reader and writer GDAL is one of the most powerful tools for fixing GeoTIFFs with metadata flaws and converting GeoTIFFs to other formats.

In use with OSM-related projects

• JOSM Elevation plugin - Uses SRTM data to display terrain elevation at the mouse location on the map and provides SRTM and GeoTIFF elevation visualization layers