The output of today's field survey is no longer a simple 2-dimensional contour plot. Observations completed in the field with modern surveying equipment are stored digitally then transferred directly into sophisticated software. This is capable of manipulating huge amounts of 3-D spatial data quickly into formats that are useful to architects, engineers and other design disciplines. The surveyor has the ability to create a digital terrain model (DTM) from collected data. In essence this is a spatially correct computerized representation of a site. As such, things can be added, overlaid or manipulated and dimensional information can be directly queried. The DTM is thus the starting block for any subsequent design project and can form the base information for many land and industrial GIS applications. By generating surfaces within the DTM volumetric information can be obtained. Questions concerning quantities such as cut & fill can be answered quickly and accurately. Laborious calculations, traditionally done by hand, can be performed many times at high speeds. This enables the designer to try out more options, giving greater flexibility and ultimately a more cost-effective solution. Design elements can be added to a model. For instance road alignments can be manipulated both horizontally and vertically to make best use of topography. Structures and drainage information can be incorporated, showing how they fit together and interact with each other in true 3-Dimensional space. A further benefit obtainable from the DTM is the ability to visualize a future scheme. Design information, in combination with computer graphics and digital photography, can be 'draped' over a model to form a realistic virtual project. It is possible for prospective clients and planners to enter into the model in real time, experiencing the views they would do with the real thing.