Land Surveying

National laboratory Land Surveying department is under construction. However, we have a wide range of approved subcontractors providing a conscientious and reliable services through highly-qualified surveyors. We deliver appreciable range of surveying services, in order to provide you with all the technical data and useful Information in a reliable, efficient and secure manner. We are dedicated in performing our services using the highest standards in the practice of surveying with an emphasis on quality, cost time. Most of all, we understand the need to be part of a team devoted to getting the work and the project done. Our services include but not limited to:

Topographic Survey

A survey locating topographic features – natural and man-made such as buildings, improvements, fences, elevations, trees, streams, contours of the land, etc. This type of survey may be required by a governmental agency, or may be used by engineers and/or architects for design of improvements or developments on a site.

Underground Utility Survey

The techniques used to determine the subsurface utility is Ground Penetrating Radar Method & Radio Detector Method. GPR uses high frequency electromagnetic waves to acquire subsurface information. Energy is radiated downward into the ground from a transmitter and is reflected back to a receiving antenna. The reflected signals are recorded and produce a continuous cross sectional or Profile of shallow subsurface conditions, Reflections of the radar wave occurs where there is a change in the dielectric constant or electrical conductivity between two materials. Directly over the conductor and this position or series of positions can then be marked on the ground. These positions can then be rapidly coordinated using either tachometric observations (total station) or kinematic observations (GPS) and the data recorded and downloaded for computation and production drawing files.

What we use Underground Utility survey for; Radio detection techniques are unable to detect non-metallic buried services such as plastic water and gas pipes, fibre-optics and drainage pipes that we cannot introduce a sonde into. To overcome this potentially hazardous situation, we combine the use of Radio Detection Penetrating Radar (GPR).
GPR is able to detect non-metallic as well as metallic pipes. It will also give an indication of the location and depth of buried services but will not them.
Changes in conductivity and in dielectric properties are associated with natural hydrogeology conditions such as bedding, cementation, moisture, clay content, voids and fractures. Large changes in dielectric properties often exist between geologic materials and man-made structures such as buried utilities or tanks. The Radio Detection instruments are used to point the subsurface utility accurately. For the most reliable determination of position, the optimum method is to clamp the Frequency Unit on to an exposed pipe or cable whereby signals then transmitted along the utility and can be detected by receiving unit A maximum signal is returned when the instrument is located directly over the conductor and this position or series of positions can then be marked on the ground. These positions can then be rapidly coordinated using either tachometric observations (total station) or kinematic observations (GPS) and the data recorded and downloaded for computation and production of drawing files.

Demarcation Surveys

Cadastral surveying is that branch of surveying which is concerned with the survey and demarcation of land for the purpose of defining parcels of land for registration in a land registry. First of all, cadastral surveying is used to define the land to be granted. Later, should the owner then wish to sell off part of that land, the cadastral surveyor is again called in to partition the land to be sold. Furthermore, the services of the cadastral surveyor are required whenever a boundary beacon must be found or replaced.

Setting out survey

Known as Construction surveying, is  the process of transferring the coordinates of a building, road or structure from design drawings to the ground/site. Setting Out points can be represented on the ground by stakes, nails or bolts depending on the project specification and ground conditions.

Geodetic Surveying

Geodetic surveying is the survey in which the curvature of the earth is taken into account and higher degree of accuracy in linear and angular observations is achieved. The geodetic surveys extend over large areas and lines connecting any two points on the surface of the earth are treated as arcs. For calculating their projected distances on the plans or maps, the correction for the earth‚ curvature is applied to the measured distances. The angles between the curved lines are treated as spherical angles. A knowledge of spherical trigonometry is necessary for making measurements for the geodetic surveys.

Why we Need Geodetic Surveying?

Geodetic surveys are conducted with highest degree of accuracy to provide widely spaced control points on the earth surface for subsequent plane surveys. Provision of such control points is based on the principle of surveying from the whole to the part and not from the part to the whole, as stated earlier. Geodetic surveys require the use of sophisticated instruments, accurate methods of observations and their computation with accurate adjustment. To eliminate the errors in the observations due to refraction, angular observations are generally restricted to night and arc lamps are used as signals on the survey stations. Geodetic surveying can be divided in the following ways:

Triangulation

In this type of surveying a network of well-defined triangles are formed on the plot of land to be surveyed. Only one line known as base line and all other angles very carefully.

Reciprocal Leveling

This type of surveying is required to obtain the difference in levels between two points which are separated by obstacles. Stadia or Tachometric Surveying - This is a type of surveying in which vertical and horizontal distances are computed from stadia readings without using chain or tape.

Astronomical Surveying

It is a branch of surveying in which the meridian, azimuth, latitude, time etc. of a place on the surface of the earth are determined by observation of some bodies like the sun and the fixed stars.

Photographic Surveying

This is a method of surveying in which plans or maps are prepared from photographs taken from suitable camera stations.

Bathymetry Survey

Bathymetry can be defined as measurement of sea depths using scientific methods and technology or the study of underwater lands and their features and shapes. The act of carrying out a bathymetric study on a water body such as a lake, river or ocean is called a bathymetric survey, whose main purpose is to measure the depth of water and the shape the terrain below it. The result of this type of hydrographic survey is a clear and detailed mapping of the land submerged on the water body.

What is Surveys used for?

Bathymetry or Bathymetric surveys have several uses and the methods used to conduct them have evolved over time. One of the major uses of these surveys is to have a clear understanding of the terrain below the water bodies. A study carried out on the terrain under a water body floor can help understand the water behavior above that terrain, which is important for academic studies in schools and most importantly for safe navigation above or in those water bodies. This makes the surveys vital for small and commercial use since water is one of the worlds recognized means of transportation. A good example as to how bathymetry is used for safety is a view of a sea with commercial ships navigating through. The features and shape of the seabed can determine the temperature of the water, speed and other critical characteristics of the water above it. This is mainly because the behavior of a mass of water is highly influenced by these important factors. Since safety is a primary concern during any kind of transportation, captains have to navigate any ship with a clear understanding of how the land beneath the water they are above is like. However, it is worthwhile to note that hydrographic surveys are different from bathymetric surveys since the latter are more detailed than the former. Hydrographic surveys have less details and are, therefore, easy for captains to read through and understand for the navigators. Over the years, the methods of carrying out bathymetry have greatly evolved from the use of chains being dropped onto the sea until they touch the seabed to the use of GPS and echo-sounders to give a clear 3D representation of the seabed features and shapes. The use of long chains was highly ineffective leading to invention of more effective methods. Use of effective methods of carrying out bathymetric surveys has resulted to more accurate results and with more details pertaining to the land beneath the water and the distance from the water surface. Whereas PLUMB surveying use a great variety of sensing instruments and data may be collected from above or below the Earth’s surface or from aerial or marine platforms.