Recently i wanted to convert between geomyidae and gophernicus gophermaps. They are both simple formats, so it is fairly simple to do in AWK. Here are scripts to convert in both directions.
Even more minimal would be to have lynx and geomyidae do the work for you. For example, this log entry is served from tilde.pink, which runs geomyidae.
$ URL="gopher://tilde.pink/1/~bencollver/log/2025-11-10-convert-"
$ URL="${URL}geomyidae-and-gophernicus-gophermap-format/"
$ lynx -source "$URL" >gophermap
To convert the entire phlog to gophermap format, you could use my gopher-get.tcl script [3].
$ tclsh gopher-get.tcl "gopher://tilde.pink/1/~bencollver/log/"
Note that gopher-get.tcl depends on TclCurl. Slackware package [4].