TOPOGRAPHIC SURVEYS

The purpose of a TOPOGRAPHIC SURVEY is to gather survey data about the natural and man-made features of the land, as well as its elevations.
To meet the utmost quality of the topographic surveys, Gmantis use several technologies to obtain the accurate data. Each technique has a varying degree of success and accuracy in a given environment. When performing a topographic survey it is essential that the appropriate equipment and methodology is used in the best way for the given situation. Given below are some of the successful techniques.

DGPS Survey

DGPS is a method of improving the accuracy of your receiver by adding a local reference station to augment the information available from the satellites. It also improves the integrity of the whole GPS system by identifying certain errors.

The use of Differential Global Positioning Satellite (DGPS) technology is increasing in earth science disciplines due to the inherent benefits of obtaining accurate position locations.

Benefits include the ability to make better decisions, for example, in locating and following up on anomalies, and in improving survey cost effectiveness and time management.

Examples of typical applications include:

gmantis practice well defined methodologies in performing DGPS and total station survey, handling geospatial data, extraction from various sources and formats, data gathering to OGC compliant GIS dataset development for the best quality.

Underground Utility Survey

Underground utility survey is the process of carrying out both desk-based and site investigations using a variety of non-intrusive techniques to provide accurate plans of the buried utilities within a specified survey area.

Many benefits arise from having good quality mapping of the buried utilities of a site, including:

Gmantis use several technologies to obtain information on the position of buried pipes and cables. Each technique has a varying degree of success and accuracy in a given environment. When performing an underground survey it is essential that the appropriate equipment and methodology is used in the best way for the given situation. Each will find some pipes and cables in some situations, whereas, with an educated approach, most if not all utilities can be accurately determined in a wide variety of situations. The two most commonly used techniques are radio-detection locators and ground penetrating radar (GPR). Gmantis has huge expertise with both techniques to bring you the best survey solution.

Visual Inspections for Sewer Lines

Possible manholes, valves, vaults, chambers are opened for measuring their extents and depths. Sewers also need to be marked with the flow directions of drain tunnels, diameters and depths of tunnels. Manhole covers and valves outside the immediate site boundary are opened and marked.

Electromagnetic Locating Survey

Electromagnetic location instruments (Cable/Pipe Locator) are used to locate metallic pipes, tracer wires for non-metallic pipes, and drains. All surface features of underground utilities are recorded, including manholes, draw pits, inspection chambers, gullies, and street furnitures connected to pipes and cables, such as lamp posts, illuminated road signs and bollards, telephone kiosks etc. All underground services shall be surveyed.

Underground utilities are positioned in three dimensions at reasonable interval for each surface feature. Where bands of cables/ducts are identified, the upper and lower outer cables/ducts are traced in order to provide a cross section of the cable/duct band.
All electrical utilities (lampposts, traffic lights, low / medium / high voltage electric cables and telecom cables) are located by either inductive methods or where necessary the use of a signal clamp which makes no contact with any conducting material. For gas and water valves, locator will directly connect with the utilities without damage. Sewer manholes are examined by use of torches so that confined space entry is needed greatly reducing the chance of injury from harmful gases, rats, snakes, etc. While drains or sewers must be surveyed by lifting covers, the path of the drain is usually traced and located using an electromagnetic sonde.

The positions of utilities are marked for the surveyor to record the findings by undertaking a topographical survey and eventually prepare a map

CABLE / PIPE LOCATOR

An electromagnetic Cable / Pipe Locator is used to identify the pipe alignment. The equipment contains two parts – a transmitter and a receiver. The transmitter generates a low-frequency signal to the targeted object. The receiver can detect the same frequency signal with an aerial antenna. The pipe alignment and depth can be marked on site immediately for record.

ELECTRONIC TOTAL STATION

An electronic total station is used to record all survey details marked on site for plan preparation.

There are different levels of survey that are suggested to satisfy the various client requirements for utility tracing and mapping. Though ‘mark out’ on site may be appropriate in some instances, it is recommended that the results be provided as plots onto accurate base mapping. We can provide a range of drawing formats including CAD, DXF and DWG.

Total station Survey

Total station is a modern land-surveying tool used to accurately measure distances, architecture and geological land forms and are often used for land surveys to record features as in Topographic Surveying or to set out features (such as roads, houses or boundaries), archaeological surveys to record excavations and highway construction zones to measure the distance of an expansion, new on-ramp or other change to the traffic pattern,
Gmantis expertise in the using the total station in following areas.