Surveying question on traverse, control point and topographic survey?

Maryland Gareau: A traverse is a survey where you establish the boundaries of something. For example a piece of property owned by someone. The survey that locates the property lines actually creates a traverse of the property. A traverse is a survey that contains at least 3 lines and the total traverse starts and ends on the same point. Take a simple square that starts at a point we call A. From A go north 100 feet establishing line AB. From B go due east 100 feet to C establishing line BC. From C go due south to D establishing line CD. From D go back to A which would be due west establishing line DA. ABCDA is a traverse of 4 lines that starts and ends at the same point.A control point is something you would do say on a construction site where you need to establish elevations of things every day, like manholes, or concrete forms, or anything on that jobsite. They would establish a control point by driving a 3 foot or so piece of rebar into the ground so it is stabl! e and won't move. Then they establish the elevation of that point by using a Benchmark that is nearby. Benchmarks are located all throughout the United States and were established by the USGS years ago and still do today. These points provide accurate elevation readings above sea level. Most cities, even small ones, have several of these bench marks. But sometimes they could be a mile or so away from your jobsite, so instead of having to go all the way to the benchmark every day to establish elevations on your jobsite, you would shoot the benchmark once and then set your own benchmark on the jobsite, and it's called a control point. It's just a point of known location and elevation that you can use as a reference to establish elevations of other points nearby.A topographic survey and a traverse are not the same thing. A topographic survey establishes elevations of a bunch of points in a given area, say a construction site, a portion of a city, a new subdivision, or j! ust any area. The surveyor would again shoot a benchmark to d! etermine the elevation of their instrument, then just shoot a bunch of points to establish their elevation and location. Once you have a bunch of points, you draw the points on a map with their elevations labeled and then you draw topo lines. A topo line is a line of constant elevation. So a topo line of 500 feet means that every point on that line is at an elevation of 500 feet above sea level. Sometimes a traverse is mapped onto a topo map and vice versa, but they are not the same thing. You can do one without the other....Show more