使用图形矢量化软件实现气候曲线向数据的转化

不同区域的气候对比是全球变化研究的重要内容和手段.气候对比通常表现为气候曲线的对比.对文献中的气候曲线进行扫描并加以数字化(矢量化)处理得到屏幕坐标序列,由屏幕坐标和实际坐标的比例系数计算文献中的气候曲线拐点的实际坐标值,最终可使用这些数值再造所需的高质量的气候曲线图形.本文探讨了地理信息系统的辅助软件之一R2V的气候曲线数字化流程.

Digitizing climatic change curves with vectorization tool

To better understand hemisphere and even global climate changes, a comparison of the paleo-climatic changes was made to reveal the conditions in different regions. One component of this work is to search for the similarity of climatic curves in an identical temporal frame. If the raw data, with which a diagram in reference is plotted, is not accessible for us, we can turn to digitization. This paper takes R2V, a GIS based software, as an example to display the digitization procedure. Firstly, we scanned the climatic curve(s) present in the reference papers into the computer, then we chose 4 points, 2 at horizontal axis and 2 at vertical axis, for controlling the points and digitizing the curves using vectorizaion tool (R2V). Finally, all the x-coordinates and y coordinates were calculated based on the transformation ratios of pixel value to real value. And high quality climatic curve plotted within new coordinate frame was subjected to a comparison with our own climatic curves.