Research On Key Technologies Of Forest Resources Information Collection System Based On BDS

Forest is an important part of the ecological environment.Scientific management measures are the premise that forests give full play to economic,social and ecological benefits.Accurate and comprehensive information is an important way to improve the management and management level of forest resources.With the rapid development of positioning technology and the widespread use of mobile intelligent terminals,GIS,remote sensing,positioning,communication and other technologies are applied through mobile device development.The traditional spatial data collection service provides a new method of operation for forest resource information collection.Beidou Satellite Navigation System developed independently in China integrates three functions:communication,timing and positioning.It is suitable for complex forest environment.At present,it has achieved full coverage in the field of China and can provide services to users all day.This paper summarizes the development status and existing problems of forest resources information collection system,forestry BDS,forestry cloud service and other technologies.Based on mobile GIS technology,the business,function and performance requirements of information collection are analyzed,the overall system architecture and functional modules are designed scientifically and reasonably,and the communication,location technology and forest resources information collection system of BDS are implemented.Combining the effect,breaking through the key technology,solving the integration problem,and developing the forest resources information collection system based on BDS.The main research results are as follows:(1)Forest resources information collection system based on BDS.Based on GDAL/ORG,JTS,Osmdroid and BDSDK,a forest resource information acquisition system based on BDS was developed.In the field information acquisition,the drawing and attribute investigation of point,line and surface targets can be carried out:the raster data displayed online and offline can be loaded;the overlapping display and attribute modification of offline vector files(*.SHP format)can be supported;the positioning accuracy can be improved through Bluetooth connection with external GPS;the short message communication and RDSS positioning function can be realized based on BDS-I Bluetooth device;The user-defined questionnaire input function and temporary layer export function are realized.(2)BDS short message compression technology.Through in-depth study of BDS short message communication technology,encoding emergency business of forest resource information acquisition,compressing business coding and coordinate information based on fixed bit length algorithm,the compression rate is 44%,saving 11 bytes,which can input 5.5 Chinese characters more than before compression,effectively improving short message information load,and giving full play to the value of BDS short message communication.(3)Improved algorithm of raster data slicing.The research optimizes the slicing algorithm of raster data,instead of output re-projection data,the pyramid generation method is changed from bottom to top.The experimental results show that the improved slicing algorithm is 35%faster than ArcGIS slicing algorithm,79%faster than GeoWebCaehe slicing algorithm and 286%faster than pre-optimization slicing algorithm under the same conditions of single thread and nearest neighbor resampling.(4)High performance tile data storage technology.In view of the four commonly used tiles storage methods,the compression rate,loading time,loading speed,portability and convenience are compared in the given experimental equipment.The results show that the tile stream file occupies the least storage space,and the compression rate reaches 75.9%.In terms of memory consumption:SQLite database files consume the least memory resources;in terms of loading speed:scattered tile files load the shortest time;in a comprehensive view.Due to poor portability,scattered files are not suitable for storage with mobile devices;ZIP compressed file tiles stream set file compression ratio is high,while loading time is long,RAM consumption is large;SQLite database file loading time is short,RAM consumption is small,but the compression ratio is relatively low.