Horizontal and vertical only

I looked at the gallery, and the topics on the forum, and the Linux man page.

I see how to lay out objects on a grid (I think I understand that). Is it possible to request that lines are only horizontal and vertical?

I don’t object to crossing lines. The diagrams I want to construct have two meanings for crossing lines: They cross without touching, or they are connected where they cross. Where they are connected, there’s a tiny circle. I need to be able to specify the difference. If I can specify zero-size nodes (as well as tiny circles), that would be workable because the graphviz program would be output from another program.

There’s an example at http://vandyke.mynetgear.com/1401/docs/ALD/4_7/722348.pdf. Is this possible (preferably easy) with graphviz? If so, what should I read?

Something like this: Church / Gordon Smith / Observable (observablehq.com)

graph [splines=ortho] is what you are looking for. See Node, Edge and Graph Attributes. Unfortunately, the implementation needs a little polishing. You get what you get.