Start in your own yard.....relatives and friends property, local parks, schools, etc....Just look online to see if there any restrictions to any public sites you want to detect. The rules and regulations are in writing somewhere.....usually the city or county courthouse. Some are available online, or, just go there and look it up yourself in the files. Asking someone will likely get more of their opinion than what the actual law is, and might bring what you're planning on doing to their attention. Not something you want, believe me. Better to be out of sight and mind as most of the rules regarding public places are very vague and subject to interpretation. Learn correct recovery methods so you leave no trace of being there.