Should I use a hyphen in the term "in(-)situ visualization"?

The term in(-)situ visualization denotes a visualization or graphics that is depicted in place, for instance, a sparkline that is embedded into text.

As the dictionaries tell, the adjective or adverb in situ is written as two words. But for concatenated terms in scientific language, oftentimes, in-situ (with a hyphen) is placed in front of the main noun. Searching for the term in Google and Google Scholar, I find both alternatives about equally frequent. Also, the COCA Corpus lists both versions for related terms such as in(-)situ burning.

What is the correct spelling of in(-)situ visualization? Is there a specific rule that applies?

No hyphen needed.

In situ (adverb & adjective) is a Latin phrase (?'borrowed phrase') with a specific meaning. The same form of the phrase can be used for all purposes.

Use of the hyphen is a scholarly hypercorrection, I believe.

I agree with the lengthy reply provided by @dodgethesteamroller that ended with "Thus "in situ visualization" is unambiguous because "in situ" cannot be mistaken for two separate adjectives; there is no such thing as "situ visualization." It's fine to put the hyphen in, but it may be perceived as old-fashioned by some copyeditors."

However, I would take it one step further to drive home the importance of the rule that usage be guided by "meaning clarification". Here's a simple rule: "If italicizing, then no hyphen. If not italicizing, then hyphenate." Either method avoids confusion in phrases like “in in vitro experiments” The double "in in" is not uncommon in scientific writing. Using both italics and hyphen is overkill and a good example of hypercorrection.