Adjustment computation of HASM: a high-accuracy and high-speed method

Abstract

We developed a method for high-accuracy surface modeling (HASM) in terms of the fundamental theorem of surfaces, which has theoretically found a solution for error problems. However, the computing speed of HASM was too slow to be widely applied in practice. Thus, adjustment computation of HASM (HASM-AC) is developed in this article. For comparatively testing HASM-AC accuracy, a mathematical surface is first selected so that the true value is able to be predetermined to avoid uncontrollable data errors. The numerical test indicates that HASM-AC has the highest accuracy and its accuracy is 20.67, 15.67, and 14.67 times higher than the inverse distance weighting (IDW), kriging, and spline, respectively. Then, a 0.4 km × 0.5 km rectangular area is used to test the effects of different spatial resolutions and sampling intervals on accuracy. This real-world test demonstrates that HASM-AC accuracy increases at a much better and stable pace as the spatial resolution becomes finer and sampling intervals get shorter, compared to the classic methods. Finally, the computing speed is tested in an area with 6000 × 6000 grid cells where Qinghai, Gansu, and Sichuan provinces meet. The computing speed of HASM-AC is 11, 8, and 563 times faster than IDW, spline, and kriging, respectively, which makes HASM-AC able to process data in a huge size and make real-time visualization realizable. In short, HASM-AC performs best in both the numerical and real-world tests.

Keywords:

• HASM
• adjustment computation
• accuracy
• computing speed
• real-time visualization

Acknowledgments

This work was supported by the China National Science Fund for Distinguished Young Scholars (40825003), by the National High-Tech R&D Program of Ministry of Science and Technology of the People's Republic of China (2006AA12Z219), by the Free Research Project of State Key Laboratory of Resources and Environment Information System (081105), and by the National Key Technologies R&D Program of the Ministry of Science and Technology of the People's Republic of China (2006BAC08B).