【正文】 ing and mapping personnel do not reach the position measurement, etc. (4) perating. Have certain perability, laser can perate not too dense vegetation and so on to reach the surface of the target entity, instant access to the surface of the target entity point cloud information in great quantities, the point cloud information can describe different levels on the surface of the object geometry information. (5) has the characteristics of high precision and density. Laser scanning measurement technology can quickly obtain the target space information of large area, through to the target scan directly to describe the target characteristic, using the large lattice and the dense grid to get the target information, the spacing between the sampling point is. (6) laser scanning measurement technology has the operation cycle is fast, easy to update, and timeliness is strong wait for a characteristic, at the same time, direct access to digital signal, digital features. application field Due to the 3 d laser scanner technology is particularly suitable for the surface of plex objects in the measurement of large area, so its application range is very wide. Relics repair: repair of damaged cultural relics, noncontact measurement, the traditional measurement is not up to, but it can make full use of laser scanner noncontact measurement features, as well as high resolution and high accuracy of point cloud data, obtaining fine structure on the surface of the building, provide the repair data, precision measurement and repair of cultural relics. Slope deformation monitoring, 3 d laser scanning technology can obtain high density, high precision of 3 d point cloud data, therefore, on the slope deformation monitoring can 20 reflect the overall slope deformation trend and scale of the operation process is scanned regularly on the slope, the superposition of two scanning point cloud data together, and then by the processing software analysis before and after the difference of two point cloud data, thus the deformation trend of slope and the order of magnitude. Mining subsidence monitoring, because of 3 d laser scanning technology has the characteristics of fast and high resolution and high precision for mining subsidence monitoring in is, can be on the surface of the mobile can quickly obtain the space location of the target area and the vertical change of the relative position to determine the surface movement of subsidence area. Urban cadastral survey: in the town cadastral survey of the past, the results of the survey for datum and report form, the more poor availability and 3 d laser scanner can produce a threedimensional image of the image, to obtain threedimensional point cloud data modeling, convenient to measure on the puter, have greater precision increase, of course, this is just a portion of their application due to its good technical superiority, industrial medical measurement in reverse engineering of digital city, etc. Different applications can be very good. Because the 3 d laser scanning technology has good technical superiority, has bee a new hotspot in the field of surveying and mapping at present, although the applications of 3 d laser scanning system research is still in its infancy, but has got good application in engineering construction with the deepening of the research and bined with other measurement technology, 3 d laser scanning technology will be more widely applied. Chapter 3 3 d laser scanning application in land reclamation the subsidence monitoring Because of 3 d laser scanning technology is quick, the resolution, high precision 21 characteristics of mining subsidence monitoring is going on, can be on the surface of the mobile can quickly obtain the space location of the target area and the change of the vertical position, to determine the surface movement of subsidence area. the feasibility 3 d laser scanner to get point cloud data after data pretreatment, model, finally get high precision DEM model, a process application software of 3 d laser scanner kit can be pleted. Will substracting the DEM model of the last observations for the first time, that is get the whole of subsidence area corresponding to the arbitrary coordinate value, then the area is divided into a certain size of grid, the output geodetic coordinate grid nodes and sink value, notes for the x, y, h, is get the whole data of subsidence area. Because of 3 d laser scanning has no fixed point, so can39。t have too much difference. To be performed and, if the surface vegetation, the vegetation, the ground vegetation of 3 d scanning technology is not mature, can lead to lower precision. (3) the scanning distance and the sampling point spacing. Has much effect on the precision of scanning, scanning distance is not within the measuring range can reach the same accuracy and precision in the far distance may appear serious attenuation, and if the log is too short, and can lead to more stations, big workload. So should according to the actual situation to choose the appropriate scanning distance. Sample point spacing mainly determines the modeling accuracy, generally in a few mm to tens of mm, the smaller the spacing between the modeling precision is higher. But the scanning time will be very long, in the mining area terrain scanning, with dozens of mm spacing, specific situation according to equipment performance and scanning range. So under the condition of the instrument have determined to choose the appropriate scanning distance is the key. Coal mining subsidence monitoring accuracy requirement is in monly 10 mm [12], if the 3 d laser scanner to scan the precision of the surface can be obtained in 3 ~ 5 mm, on the basis of plus connection error and stability of bp and coordinate conversion error can pletely satisfy the requi