Recently, I have been working on algorithms which need elevation data as well as Land Cover data, with world coverage. Google has an excellent elevation API however free usage comes with a limit.
While searching, I came across a dataset in geotiff format for landcover as well as a processed version of world elevation. Elevation data comes in various resolutions (250m, 500m, 1km), landcover is 500m.
So how do we read it? In python its quite easy to use osgo/gdal library and read all bands. Geotiff is a raster file and values can be packed in every band (which is basically a 2d array).