Articles in the Surveying Category
With maturation of Geographic Information Systems (GIS) technology, the consumer community as well as decision and policy makers have quickly realized the importance of making sound decisions based on information derived from properly designed geospatial databases. Organizations have created proprietary geospatial databases and governments are rethinking the contents of the National Spatial Data Infrastructure (NSDI). Extensive geographic data acquisition programs including satellite imagery, digital aerial photographs and Light Detection and Ranging (LiDAR) systems at varying ground resolutions, as well as land parcel data are currently in progress around the world. Enabling technologies such as Global Positioning Systems (GPS) and digital image processing software have…
Ground Penetrating Radar (GPR) provides a picture of the different materials or structures underground up to a few meters of depth. To provide a 3D map of underground objects such as pipelines, the georeferencing horizontal tolerance should be around 20 cm, a figure achievable by GNSS systems. The conditions of GPR urban surveys, though, make it impossible to rely on GPS alone for positioning. In front of large blocks…
In general, measurements are only “legal” if they are “traceable” to primary standards of measurement. A GPS measurement is “legally traceable” if: (i) it is carried out using the various test/calibration procedures as required by the Guidelines, and; (ii) the survey has followed the “recommended practices for field and office procedures” as described in the Guidelines.
A GPS system testing/calibration program…
It was in the late 1950s that the Tellurometer hit the surveying profession. Certainly it was not the first EDM instrument on the market, that title goes to the Geodimeter which appeared in 1947, but there was a difference. The Geodimeter worked on a light source and as such its maximum range was limited by visibility. The Tellurometer operated on a radiowave which could penetrate most weather conditions and achieved distances up to 100 miles…
Generally, the entire railway line is divided into several sections, and each section is fi nished separately.
Firstly, we need to collect the existing information of one section, such as map and control points. Then, survey the topography of the working area, select position of control points, set the control point network, and produce the control points by GPS static survey…
There are generally 2 types of users of DGPS for professional survey one is the National Mapping Agency and other large govt. organization who undertake Survey projects and the 2nd category is comprising of private survey set ups most of whom are first time users of DGPS and use DGPS to cut down on the time and efforts Involved in surveying with ETS (electronic total station) along with spirit levels…
In the rapidly changing economic, technological, political, and social environment that characterises the world as we see it in the 21st Century, every profession faces major challenges, surveying being no exception. While some of these challenges are common across all professions, others are specific to the surveying community. In this discussion I choose to separate the challenges facing the surveying profession into these two categories…
There are many traditional surveying methods used for the large-scale bridge structure deformation monitor such as the accelerometer measure, the total station surveying and the laser collimation, but these methods are limited by its function of which the continuity, timeliness and automaticity can not meet the need of the large-scale construction dynamic monitor. In recent years, with the GPS hardware and software technology developed, especially the GPS receiver with the high data-collection frequency (for example 10Hz even 20Hz[1][4]) appearanced as well as the GPS data processing was improvement, the GPS-RTK technology applied in large-scale bridge dynamic deformition monitor with real-time or quasi-realtime has become true[2][3].
Geomatics is the art and science of measurements on the surface of earth including what is below the earth and in the oceans. This is the simplest form of definition; more exact and elaborate definition has been produced by FIG¹. In other simple words Geomatics is the new terminology for the centuries old profession of Surveying and Mapping…