You need to download only the tiles covering your area of interest. You are also required to download, along with the data files, the esri header files .hdr for Arc/INFO and ArcView that accompany the dataset.
Readglobe should work also with older versions of the dataset which came in different tiles, provided that the proper header files are available.
For compiling there is no configure script, so you should edit the Makefile and uncomment the proper sections depending on having standard Vis5d or Vis5d+ and working on a little endian machines such as i386 (PC's) and Alpha or on a big endian machine like most of the others.
The syntax for running readglobe is:
readglobe -b <lonmin> <lonmax> <latmin> <latmax> [options] file1.hdr [file2.hdr ...]options currently available are:
-o <output file> name differently the output file (default EARTH.TOPO)
-s shrink the requested area to the innner closest gridpoints
rather than enlarging it (as done by default)
-a <n> average the data over nXn points boxes
-m <z> set the height of the missing (sea) points to
<z>, default 0.
You can specify as many header files as you want, those that describe
an area outside the requested one are just skipped. The data files
must be in the current directory. Notice that the program understands
only a minimal subset of the esri header file keywords necessary to
identify the GLOBE data, so it is not guaranteed to work with other
header/data files; moreover it contains a workaround for the problem
that currently the header files indicate, as data file name, the
header file itself and not the data file (I wonder whether this is a
bug or a "feature" of the dataset).
Notice that, in order to appreciate the increase in the topography resolution, you may have to run vis5d with the -hirestopo option.
The program is experimental, it appears to work on the European area, but I cannot guarantee that there isn't any one-grid-point shift somewhere or that it doesn't crash if used with tiles different from the ones I tested; if you think you found a bug, or you have suggestions for improvement to readglobe, let me know.