Three Different Kinds Of Geographical Surveys

Survey is a very broad term covering statistical surveys, geographical surveys, Archaeological survey, Astronomical surveys and so on. Our concern here is about geographical surveys; in this category among the many different kinds of surveys three of the more commonly used ones are topographical, land and underground utilities surveys.

Topographical Surveys

Topographical Surveying is the study and measurement of the Earth's surface. This can reveal what natural or man-made geographical features exist in an area, large or small, the contours and shapes of the features themselves and even vegetation and the influence of human presence. The objective is to produce a three-dimensional map.
In order to provide this kind of accurate detail of the various levels and contours of the land, aerial surveys are conducted, and then at ground level survey teams with portable surveying equipment establish vertical and horizontal control points to confirm accuracy. These days the data is collected and generated electronically.
Fed with all the data, computers combine distances, angles, and elevations and produce pictures, using contour lines, hypsometric tints and relief shading.

Land Surveys

Land Surveying is the measurement and accurate determination of the three dimensional positions of various points on a terrain. The purpose of this is generally to determine boundaries. Surveyors produce land maps marking out areas of private, communal or government ownership limits. This is constantly being done when there are serious property right disputes or changes are planned for the area, such as for sub-dividing properties, new residential or town-planning layouts, when roads or other engineering structures are planned, or for the determination of ancient boundaries for historical or archaeological purposes.

Underground Utilities Surveys

Underground Utilities Surveying is one of the most tricky and difficult types of exploration. Surveyors have to determine what is underground that cannot be seen. Before starting any development project such as construction of buildings or laying roads it is essential to get the details of any underground utility in that area. These may be drains, electrical or gas cables, sinkholes, water pipes or water pockets or buried tanks.
The first level of exploration is to collect every drawing, plan or bits of electronic data available for the area. This is often not totally accurate, but gives an idea of what installations were situated in the immediate area.
The next level involves picking out visible features, such as manholes, inspection hatch covers, metres, electrical poles, etc. Straight lines showing the shortest distance between them are drawn, and this narrows down the search. However these lines cannot always be totally relied on as rocks and other underground barriers can cause deviations, and sometimes the pipes or cables don't run from the centre of each inspection element to the next, but slightly to one side or the other.
An indirect survey involves the latest technology, such as ground penetrating radar that penetrates the ground, X-rays, and frequency resonance.
If uncertainty still persists, the last step is drilling or digging potholes at regular intervals to confirm any of the data collected by the above methods.