Acta Geodaetica et Cartographica Sinica ›› 2016, Vol. 45 ›› Issue (1): 112-118.doi: 10.11947/j.AGCS.2016.20140598

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An Improved QTM Subdivision Model with Approximate Equal-area

ZHAO Xuesheng, YUAN Zhengyi, ZHAO Longfei, ZHU Sikun   

  1. College of Geoscience and Surveying Engineering, China University of Mining & Technology(Beijing), Beijing 100083, China
  • Received:2014-11-17 Revised:2015-06-25 Online:2016-01-20 Published:2016-01-28
  • Supported by:
    General Program of the National Natural Science Foundation of China(No. 41171306);Young Program of the National Natural Science Foundation of China(No. 41201416)

Abstract: To overcome the defect of large area deformation in the traditional QTM subdivision model, an improved subdivision model is proposed which based on the “parallel method” and the thought of the equal area subdivision with changed-longitude-latitude. By adjusting the position of the parallel, this model ensures that the grid area between two adjacent parallels combined with no variation, so as to control area variation and variation accumulation of the QTM grid. The experimental results show that this improved model not only remains some advantages of the traditional QTM model(such as the simple calculation and the clear corresponding relationship with longitude/latitude grid, etc), but also has the following advantages: ①this improved model has a better convergence than the traditional one. The ratio of area_max/min finally converges to 1.38, far less than 1.73 of the “parallel method”; ②the grid units in middle and low latitude regions have small area variations and successive distributions; meanwhile, with the increase of subdivision level, the grid units with large variations gradually concentrate to the poles; ③the area variation of grid unit will not cumulate with the increasing of subdivision level.

Key words: discrete global grid system, QTM, parallel ring method, geometry deformation of grid

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