基于ENVI/IDL的多源遥感数据覆盖范围快速查询技术及实现

Fast Approach for Querying Coverage of Multi-source RS Data and Its Realization Based on ENVI/IDL

针对大范围遥感应用,前期工作是查询某数据源的覆盖范围以及被云雪覆盖区域或未覆盖区域是否有同尺度的数据源替代,由于各种卫星数据的查询系统一般是相互独立的,使得工作繁琐费时。介绍了在ENVI/IDL软件环境支持下,多源遥感数据覆盖范围快速查询技术及其实现。首先,根据元数据获取影像快视图4个角点的经纬度坐标,并生成矢量落图文件;然后,通过算法检测出影像快视图有效范围4个角点的像元坐标;最后,对相同数据源的一批快视图进行自动几何校正,生成带有经纬度坐标信息的GeoTiff格式图像,从而使得各种数据源的快视图都可以在GIS软件中与行政界线一起叠加显示。由于可以对大量数据进行批处理,并且在设置好初始元数据格式后,不需要任何人工干预,极大地提高了多源数据覆盖情况的查询效率,从而可以快速、准确地判断有效数据的覆盖范围是否满足应用需求。因此,该方法具有很大的实用性和推广价值。

A preliminary work for remote sensing applications on large region is to query the coverage of certain remote sensing data and to know whether there are substitutes with similar scales for regions covered by clouds or snows,or for regions not covered by this kind of data.Generally speaking,the querying systems of all kinds of satellite data are independent,which makes the querying for coverage of multi-source remote sensing（RS） tiring and time consuming.To fast query the coverage of RS data on large regions,a batch processing approach is proposed and a tool is developed based on ENVI/IDL.Firstly,the metadata are read from the text file.Secondly,the outline vector is generated with desired attributes.Thirdly,the four corners of the valid range of image data are detected.Finally,the preview picture is registered automatically.The georeferenced images and the outline vectors can be overlaid correctly with the vector of administrative boundaries according to their geographic coordinates.After proper metadata format selected and the input directory and the output directory input,the software begins to run in the batch mode without any interactive.It will finish the task very soon.This approach can greatly improve the query efficiency of multi-source RS image coverage.Then decision can be made according to whether the valid coverage can meet the demand of the application.Thus the approach mentioned above and the software developed according to it are very practical and worthy of popularization.