2000 Aerial Photo Mosaics - Upper Mississippi River System -- Pool 15

The U.S. Geological Survey's Upper Midwest Environmental Sciences Center (UMESC) collects aerial photography of the Upper Mississippi River System (UMRS) floodplain on a regular basis. These data are used to support the Center's long-term goals of understanding the UMRS and developing useful products for the Long Term Resource Monitoring Program (LTRMP). In 2000, 1:16,000-scale true color aerial photos were collected on the Mississippi River from Cairo, IL to Minneapolis, MN and the on Illinois River from its confluence with the Mississippi near Grafton, IL to Lake Michigan/Chicago, IL. The photos were collected using a 60% stereo overlap between photos in the same flight line and a 30% overlap between flight lines. At the time this document was prepared, UMESC was in the process of scanning, georeferencing and compiled approximately every other photo into georeferenced mosaics for the navigation pools. These mosaics are served as compressed .sid images, so they'll be easier to download vial the Internet. Note: While the photos have been georeferenced, they have not been orthorectified.

美国地质调查局（U.S. Geological Survey）下属的中北部环境科学中心（Upper Midwest Environmental Sciences Center, UMESC）会定期采集密西西比河上游流域（Upper Mississippi River System, UMRS）泛滥平原的航空摄影数据。此类数据用于支撑该中心的两大长期目标：一是深化对密西西比河上游流域的科学认知，二是为长期资源监测项目（Long Term Resource Monitoring Program, LTRMP）开发实用型业务产品。
2000年，该中心完成了两片区域的航空摄影作业：其一为伊利诺伊州开罗至明尼苏达州明尼阿波利斯段的密西西比河河段，其二为伊利诺伊州格拉夫顿附近与密西西比河汇流处至密歇根湖/伊利诺伊州芝加哥段的伊利诺伊河河段，采集的均为1:16000比例尺的真彩色航空照片。本次航摄设置了如下重叠参数：同航线照片间立体重叠度为60%，不同航线间重叠度为30%。
在本文件编制之时，UMESC 正处于照片扫描与地理配准的工作阶段，并已将约每隔一张的照片拼接为适配各通航渠段的地理配准镶嵌图。此类镶嵌图以压缩.sid格式图像形式对外发布，以便于通过互联网快速下载。
备注：尽管这批照片已完成地理配准，但尚未进行正射校正。