We have been using Gemini 1.5 Flash at enterprise scale on a massively varied, form based document dataset and we have yet to see hallucinations, on either our ground-truth dataset or in our random audits for evaluation. Just to make sure though we threw some recursion on it: we take the output and give it right back to the model with the original prompt and output and ask it how accurate it is. If it thinks it's not accurate we tell it to rewrite the original prompt to provide for a more accurate output. We then stuff that right back down its own function :)
For your use-case it would be exponentially easier as all you'd need to provide Gemini your "zones" as the JSON schema for output and it will quite reliably identify them.
For your use-case it would be exponentially easier as all you'd need to provide Gemini your "zones" as the JSON schema for output and it will quite reliably identify them.