If you want a free, legal, and modern surveying resource, consider downloading "Fundamentals of Surveying" from the National Programme on Technology Enhanced Learning (NPTEL) – not a Duggal PDF, but legally free and updated.
Most engineering colleges subscribe to digital libraries like , Scribd , or INFLIBNET . If you log in via your college proxy server, you can often view or download the official PDF for free. survey sk duggal pdf