The 3D laser mobile measurement system can collect 3D laser point clouds and panoramic image data on both sides of the road during fast driving.With the development and application of panoramic laser mobile measurement method,it can solve the problem of rapid acquisition of street tree data along both sides of the road,and quickly extract the thematic vector elements of urban gardens through indoor automation and manual interactive operation.It can greatly reduce the labor intensity of field operation and reduce the production cost at the same time.

I.Project requirements and difficulties

　　The project is located in an urban area in central China,with large traffic flow and scattered trees.The traditional surveying and mapping operation mode has high intensity and low efficiency.At the same time,GNSS signals in some areas are poor,which brings great challenges to the surveying and mapping work of operators.

　　Achievement requirements:collect 3D laser point cloud and 3D real scene data on the road and both sides,use the supporting processing software to quickly collect,update and extract attribute information of garden trees,and finally establish a set of garden information basic database with unified spatial coordinates.

　　Project difficulty:large traffic flow and scattered trees;GNSS signal in some areas is poor.

II.Solution

　　1.Field data acquisition

　　Based on HiScan-Z 3D laser mobile measurement system,the information acquisition equipment of garden trees can collect 3d laser point cloud and 3D real scene data of road and both sides during rapid movement.The point cloud frequency of the panoramic mobile measurement system is 1 million points/s.It is collected at a speed of 50km/h.The 10km effective point cloud data is about 6GB.

　　2.Internal data processing

　　Based on the obtained 3D laser point cloud and real scene data,the supporting processing software can quickly collect,update and extract attribute information of garden trees,and some feature information(DBH,canopy diameter,height,etc.)can be extracted automatically.Using automatic analysis and extraction program combined with manual inspection can improve the indoor processing efficiency by more than 40%compared with pure manual extraction.Finally,a set of basic garden information database with unified spatial coordinates is established.

   　3.Application service

　　Based on the basic garden information database,a 3D real scene system platform for garden information management and service is provided through 3D real scene and 2D/3D management display technology.The real scene platform can realize seamless integration with the business platform.On this basis,a professional business management platform for classified management,tracking and monitoring of tree structures and surrounding features can be established,which can assist in historical data comparison,seedling growth monitoring,rainwater statistics,survival rate analysis,etc.

III.Project summary

　　In this project,the 3D laser mobile measurement system is used to collect the garden tree information in the field.The street tree is extracted automatically based on the point cloud in the field.Combined with manual inspection and modification,the workload of field collection of traditional measurement is reduced and the work efficiency is improved.Through the comparison and verification of collection and processing in the experimental area,it can greatly improve the production efficiency and provide a more convenient and effective solution for the production and updating of urban thematic map data.