为了分析GIS图上地理曲线的定位精度, 首先探讨地理曲线的表达与定位误差, 区分“数字曲线”和“连续曲线”两个概念;然后结合由数字曲线生成连续曲线的GIS算法, 建立连续曲线的误差带模型, 并导出地理曲线长度的误差估计公式;最后通过算例说明地理曲线误差带的可视化方法和曲线长度误差估计公式的应用。

To analyze positional accuracy of geographical line s in GIS, this paper begins with a discussion on the representation and positional errors of linear features. We make a clear distinction between digital lines in spatial databases and continuous lines in the natural world. Using algorithms f or generating continuous curves from digital lines in GIS, we develop several er ror band models for continuous curves and derive numerical relationships for est imating errors of line length. Examples are provided to show the visualization o f error bands of geographical curves and the use of error equations of line leng th.