I took a look at the book Garbology* to see how the author uses the word "survey". In most cases, he means a voluntary questionnaire used to collect information from people about their habits. As he points out, data collected from human surveys can be biased, because people may not respond accurately for many reasons.
In other cases, he uses "survey" to refer to data samples collected from a physical location. He talks about systematic study of plastic pollution at a section of California coast and another study of pollution in the Pacific Ocean.
In all cases, surveys are designed to gather facts from a small set to help you learn about the whole population.
*I looked at the 2012 edition of Edward Humes' Garbology via Google Books. We have the print edition of the book in our collection.
I hope this answers your question. If not, or if you have additional questions, please feel free to respond.
Sincerely,
Michael Davidson
Lamson Library & Learning Commons