What is the difference between land surveys and remote sensing?

Answer 1

A land survey is carried out by a survey crew and is overseen by a professional land surveyor (PS or PLS in most places).

Land surveys can serve many functions, but ultimately take measurements of land and describe land using measurements. Some uses are wetland delineation, determining property boundaries, staking out roads over many hundreds of miles, and so on. Again, most surveys will require a licensed land surveyor.

Remote sensing is simply taking measurements from a distance, or without direct contact. Using LiDAR to determine tree height is remote sensing - using a tape measure or stick is not remote sensing, but serves the same purpose. Remote sensing would allow you to measure many trees very quickly without having to be on the site of a tree, as an example.

Keep in mind many surveyors are turning to drones and remote sensing as part of their workflows. A surveyor can provide expert knowledge on water drainage and a drone can help accomplish that.