This is an inefficient format, so be warned: you are going to get a datafile.
The $partialdiff sub X$ $partialdiff sub Y$ [ NOAA NGDC GLOBE topo ] data are available as a columnar table,
i.e. as multiple columns of data, intended primarily to be read. However,
if you have other intentions for this table, or simply do not like the default choices, you may want to choose from the columnar tables with options.