2 minutes would be the longest I would spend surveying. The most of the time is for collecting trigger words.
Surveying is a part of previewing by default, [you cannot preview without surveying]. Surveying is getting a sense of the order of the book, whether it has been divided into parts that explain specific concepts. noticing the type of fonts used. If there are any patterns that stand out in the presentation of the text, like boxes that contain stories or examples tips and hints. The overall look or presentation of the text.
In the additional actions of previewing. You allow your self to notice words here and there. Get a sense of the language style that the author uses. Complexity of the passages. You might already notice whether the author has a positive voice or a negative voice. And down the trigger word.
It's not necessary to seperate surveying from previewing but if you wanted to it would be like in shopping. Surveying is just looking and noticing where everything is and previewing is picking up what catches your interest and putting it back as you happen to move past.
Alex
