Good question. For mathematicians and linguists, a graph is a diagram that consists of nodes and edges. For the rest of us, who must communicate using words that we hope others will readily understand, graphs are diagrams that consist of points and lines between them. For our purposes, any diagram that consists of points and lines is a graph.
A graph is a convenient way to show connections between things. Flow charts, for example, are a specialized kind of graph. So are corporate organizational charts. Sometimes people draw graphs when they are brainstorming, by putting words in little bubbles and then drawing lines between them to connect them. There are several task-management packages that visualize your task list as a many-tentacled Hydra shooting out seven new tendrils whenever you hack one off. Or maybe thats just my tasklist.
Anyway, those are all graphs. Points with lines connecting them.
When you put arrows on the lines, you’re making a directed graph, which is especially useful for making things like flowcharts and corporate org charts: You want to know which steps to do first, and you want to know who your boss is. This sort of arrangement is also useful for labeling the parts of a clause:
Here we have a Clause that consists of a Subject, a Verb, and an Object. The Subject consists of a Noun Phrase (NP), which in turn consists of the article, the, and another NP consisting of two words. The Object consists of a NP that in turn consists of two words. At any point, you can find all of the parts or constituents of any given label in the graph by following the arrows downward until you reach the end. For example, to find all the parts of the Subject, you would follow the arrows down from Sb, through the two NP labels, and down to the words: The whole earth. Thus, this graph tells us that the Subject of our clause is the whole earth.
This is a fine way to diagram a sentence; but while it works well for short sentences, this presentation does not lend itself well to displaying entire texts, such as the Bible. If, however, we turn the graph on its side so that the text reads from top to bottom along the right-hand margin, we get a graph like this:
Now we can have an infinitely long running text that reads from top to bottom, and that’s just what we have when we look at a Logos Bible Software syntax graph:
What this graph really tells us is which words belong to which structures and how those structures come together to form a clause. That’s actually quite a lot. If I were to write this out in prose, it would look something like this:
We have a clause, which contains a discourse-level consecutive waw, a predicator, a subject, and then a subject complement. The subject is a construct noun phrase, which consists of the word all and a definite noun phrase consisting of the words the and land. The subject complement is uh, never mind. Just look at the graph!
What Logos Bible Software can add to these graphs which are already quite useful in their own right is interactivity. That is, the graph can change its presentation in response to the actions of you, the user. Let’s say you want to examine the subject complement of the sentence, so you point at that label on the graph with your mouse:
Immediately, the graph changes its presentation in order to highlight the subject complement: All of the structures that are in it, including the words that it consists of, are highlighted in orange. It’s also a part of higher-level structures, which can be found by following the blue arrow backwards to the clause.