Topography is generally known as the study of earths surface, and its features and shape. It also gives the description of the features (such as surface, shapes, vegetation cover & elevations), depicted in maps which are called “TOPO. In essence, topography mainly concerned with local details such as vegetative and man-made features including local history and culture. More specifically, topographic surveying involves the gathering information on terrain, three dimensional details of the surface including recognizing the specific landforms. In modern terms, it is the generation of data digitally or electronically. The outcome of topographic survey is the graphic representation of a given land parcel on a map using several techniques such as contour lines, Hypsometric tints and relief shading.
A Topography Survey is used for wide variety of applications such as military planning, geological exploration, civil engineering, construction, public works and reclamation work. Depending on the type of application the objectives of using topographic information may vary. For example, detail information terrain is and surface features are important for the planning, designing and implementation of a large civil engineering or irrigation or public works project. In other words, topography surveys will help the planner to determine the features on given land surface and any special location in terms of coordinates (latitude, longitude, and altitude). Similarly, it will help to identifying special features pertaining to typical land usage patterns and vegetative cover.
There are variety of methods used in topographic surveying. For example, direct surveying, remote sensing, aerial and satellite imagery, photogrammetry radar and sonar. The most appropriate method to be used depends on the scale, size and complexity of the are subject to study. Also, it depends on the accessibility and the quality of existing surveying information.
It is important to note that direct surveying is still an important method for determining accurately the terrestrial or 3-D space position of points and the distance and angles between these points. Although the recent advances in surveying (such as remote sensing, GPS, Satellite Imagery, Photogrammetry) have helped us to speed up information gathering and accuracy, the traditional survey is still useful by providing basic control points and necessary framework for topographic survey. As such, it is essential to realize the importance of direct survey and how it complements with the modern surveying techniques used for topographic surveying
A topographic map (‘topo’) can be considered as a site map showing many features of a site including contour lines. In addition, topographic map provides you with features such as natural drainage patterns, locations of hills, rock outcrops, valleys and other man-made and natural features.
Similarly, the topo map provides you detailed locations of buildings, settlements, utility, land use patterns, and other relevant information which is important for planning and design of large civil engineering projects.
A topographic maps or surveys are extensively used for many engineering projects ranging from irrigation, dam, land settlement, large housing projects, trans basin canal project, pipe laying, etc. As such, it is very popular among engineers, architects or building contractors who need to know detailed information regarding overall site condition related to elevations and grade. This information given in topo maps, may be used for site improvements, estimation of volume of earthworks to be hauled or removed, or for many numerous construction and development projects.