Research On The Data Currency Of The Second National Land Survey Based On GIS

Abstract:The second national land survey gives an overall, detailed land use situation and all kinds of land resources of the whole country. The massive data achievements accumulated during the second national land survey are fundamental data for the Ministry of Land and Resources, and are widely applied in resource environment, basic mapping and surveying, marine, transportation, etc. The authenticity and accuracy of the data achievements play an important role in development plan, command decision of every field. The quality check strategy and updating mechanism can be used to keep the currency of the data achievements. However, no further study has been launched upon the currency of the data achievements. Thus, we hold that how to make a system and complete evaluation upon the currency of the data achievements is one important problem that needs to be solved in land.In the data currency evaluation, some problems appear, for instance, lack of theory model and low interpretation efficiency which is caused by large volume of data. In order to improve the data utilization, the paper makes a further research on the theory model upon the currency of the data achievements and key technologies of image data processing. The main researches of this paper are as follows:1. We put forward an evaluation model upon the currency of the data achievements, define the construction land currency index and the change correctness index of arable land occupied by construction. Using the influence degree upon the currency of the data achievements of the two currency indexes, we present an integrated evaluation strategy upon the currency of the data achievements.2. We make research on automatic extraction and change detection on construction land, construct the construction land rules. We make full use of feature information to extract construction land and improve interpretation efficiency by object-oriented method based on rules. Combining with land change survey data, we detect the changing part of construction land using overlay analysis.3. We improve the normalization difference building index and make it can be used to extract construction land in Digital Orthophoto Map (DOM) which owns only 3 visible bands. We add improved normalized difference building index into the construction land rule.4. We put the 9 counties in Hangzhou as research region, process the experimental data, calculate the construction land currency index and the change correctness index of arable land occupied by construction, evaluate the currency of the data achievements in research region, analyze the currency results and validate the efficiency of research achievements.