Research Of Cadastral Investigation System On Android Platform

Cadastral Investigation is the groundwork for land management, which consists of Authority Investigation and Cadastral Survey. Authority Investigation aims to collecting social information of the parcel, such as ownership and boundary line, and Cadastral Survey attend to collect the accurate location information and other messages like area or shape of the parcel. With the continuous development of economy, which presented as continually urban expansion and quickly urbanization process, the updating speed of construction land accelerates, leading to more onerous tasks of cadastral investigation. What’s more, the routine measurement in urban becomes more difficult as it’s hard to make control measure or layout the traverse network. A method which splits the survey area into small areas is studied in this paper, so that less control-points are used for large area’s measurement.The main contents of this paper are as follows.The measurement technology based on multi-blocks has been researched. After the survey area is measured by dividing into blocks, which can be easily measured by free-station positioning technique, the join-points between blocks have been used to complete figure adjustment and coordinate unification, and the control points are used to convert the survey data into results-coordinate. The maximum range of one block should be less than 6.28 km2, which is determined by the qualitative and quantitative analysis of error resources. Ggross error is detected by the trace of param-matrix, and the remeasure process for join-point with gross error is designed based on the theory of total station measurement.The digital authority investigation system and cadastral survey system based on the multi-blocks measurement technology are designed. The authority investigation system is designed on tablet computer by bringing functions such as digital parcel chart and real-time evidence capture, and the cadastral survey system is developed with the measurement technology based on multi-blocks.An optimization has been made for the data transmission between mobile device and total station, which will be more reasonable as it can reduce BER (bit error rate) by increasing analysable ratio.Embedded GIS data structure has been designed for survey application. Treelike indexing structure has been used in data structure after analysis of survey requirement, and more details about its creating, modification process has been discussed in this paper. Finally, the data structure has been developed on android platform, and comparative analysis about memory consumption with the JTS open source tools has been made to confirm that they are equivalent memory consumption.Two sets of softwares are developed on android platform for the two systems mentioned above. During the develop process, strategy pattern is used to develop survey tools, the display optimization is designed by splitting screen into logic layers, the configuration file is projected for flexible property modifying which perfecting the previous software developed on PDA. What’s more, the implemention about data collection process is analyzed.Accuracy test of the cadastral survey system is made by a professional organization, verifying the precision of boundary points measured by the new system is less than 0.05m, which meets requirements of "Specification of City and Town Cadastral Survey". The Demonstration Application about the cadastral survey system is carried out at LianHua town in ChangSha, Hunan province, shows that the new system is effective.