The recent advances in technology have resulted in 3-D Mapping software which has been very popular among engineers, planners, mapping technicians, surveyors, and GIS professionals. The LIDAR (Light Detection and Ranging) Contour mapping is one of the 3-D technology used by professionals. This is very fast, cost-effective, high accuracy, high density elevation data generation mapping application for topographic surveys. Similarly, there are other 3-D mapping software available for the surveying professional. For example, Auto-CAD Map 3d software that allows direct access, edit, visualize, and analyze a broad range spatial data and CAD information using popular AutoCAD software.
The new 3-D mapping technology has enabled large topographic surveys to be carried out appreciably quicker and at reduced costs when compared with the traditional survey methods. Especially, the LIDAR contour mapping has mostly replaced traditional methods that involved surveying, which used stereo imaging and stereo plotter.
In earlier days ground and aerial surveying have been the major data generation source for digital elevation models (DEM). These older survey methods used for distance and angle measurements employing surveying equipments can provide accurate elevations at identified locations. However, these methods can cover only small areas and seems very slow. Large area surveys require wide network of coordinates or points. The 3-D mapping or GPS technologies have immensely improved the modern survey speed and accuracy or precision.
Laser based or LIDAR contour mapping and DEM generation have been become popular among many professionals. These latest mapping technology uses laser (pointing downwards) placed on an aircraft. When the aircraft glides over a terrain, the laser measures height elevation above terrain, and include other optics that allows the measurement of heights of locations directly below and either side of the aircraft flight path. With the use of precision GPS system terrain heights (on entire landscape) can be produced in combination of flying heights and laser measurements Once the height measurements are produced, these data can be combined to create a grid-based Digital Elevation Model or 3-D Mapping.
The collected data or the heights of the terrain (at fixed intervals) are stored in the computer using proprietary 3-D software. Usually, it is stored as 2-dimensional grid or the matrix of all elevation values. From the stored data a contour or 3-D mapping could be generated. Similarly, by linking or threading through the matrix, shaded or arrow maps (indicating slopes) and 3-D maps can be produced.
The Advantages of 3-D mapping using latest technology.
Accuracy: The latest technology used for contour mapping or 3-D mapping uses a combination of three well known and tested technologies. Such as LIDAR, highly accurate internal reference system (INS) and the global positioning satellite system (GPS). By integrating these technologies, it is possible to produce accurate digital topographic or 3-D map of large terrain.
Speed: The present 3-D mapping technology is very quick in generation of topographic data. For example, with the use of currently available commercial systems, a survey of one thousand square kilometers can be completed in less than 12 hours. Similarly, one hour data collection can produce 10,000,000 individual geo-reference elevation points. With this high rate of sample data, a large topographic survey can be completed quickly moreover can produce DTMs with grid intervals less than 1m.
Nonintrusive
The latest laser or 3-D mapping is a non intrusive or interfering method. Without visiting the terrain, it is possible to obtain detailed and accurate elevation information of the landscape. It is advantages in situations where ground access is not possible due limited access, or prohibited or there is risk.
Commercial airborne laser or 3-D mapping systems are offered by many instrument manufacturers. Also, various survey firms have their own custom built systems.
Land Surveys Pty Ltd are land surveyors who can also provide 3d maps as part of their services in Western Australia.
Source: iArticle.org
