Dem不确定性评价及计算复杂度分析

　Accuracy assessment with Computing Complexity in DEM

  Dem不确定性评价及计算复杂度分析

abstract:

文摘：

  The digital elevation model(DEM) is a computer representation of the earth’s surface. DEM errors are the departure of a measurement from it true value. it is elusive and constitute uncertainty. Uncertainty refers to our lack of knowledge about this error. It is generally thought that there are two reasons cause uncertain of Dem, which is uncertain of the source Dem data and of data processing such as vector map tracking, vector map editing , border jointing, TIN constitute and estimating accuracy. So the accuracy of DEM is mainly determined by error of data collection and error of elevation interpolating.

 The most intuitive way to assess the quality of a DEM is to determine the amount of error in the elevation values. Commonly describing vertical accuracy of data points used to generate a DEM is in terms of the Root Mean Square Error (RMSE) (Wechsler 1999).  There are many algorithms about evaluate error in DEM’s by point comparison with neighboring data points, if there are some of difference of the data point which exceed the threshold then we can conclude that this DEM data is not qualified. Section plane comparison is another method for DEM quality assessment. By comparison of some section plane we can get knowledge of the DEM data, then we can use mathematic method or comparison about practical section and interpolating section to assess DEM error. There are some method which is also very useful in accuracy assessment. Visual Inspection is a quick way to identify obvious logical inconsistencies and actually we use it visually detect errors in the DEM.

Computing Complexity is the Study of how do the resource requirements of a program or algorithm scale.

Here the paper presented some algorithm about position error checking and then computing complexity about it is analyzed.

    数字高程模型（DEM）是地球表面的一种计算机表示形式。DEM误差是其测量值与实际值的偏离。这种难以预测的DEM误差构成了不确定性。不确定性值得是我们对这种误差缺乏足够的了解。一般认为原始数据的精度以及数据处理（包括矢量化跟踪， 矢量编辑， 图幅接边， TIN生成， 精度评定）是DEM数据不确定性的两个主要因素。因此DEM的精度主要由数据采集和高程插值所决定。  计算复杂性是一个程序或者算法所需要的资源的一个度量。这篇文章里我们将给出一些有关位置错误检查的算法并分析了他们的计算复杂性。