1989-91 Aquatic Habitats - Upper Mississippi River System - Alton Pool

The U.S. Geological Survey's Upper Midwest Environmental Sciences Center (UMESC) has created high-resolution land cover/use data sets for the Upper Mississippi River System (UMRS) from 1:15,000-scale color infrared aerial photos. These data have been used to create a variety of products, one of which is a data set used to classify aquatic areas. The 1989 and 1991 aquatic areas data sets were created by first generalizing the available land cover/use data into a land/water data set, then reinterpreting the aerial photography within the areas classified as water to determine the type of aquatic area. Area coverage for this data set is the Upper Mississippi River between Minneapolis, MN and Cairo, IL, and the Illinois River from its confluence with the Mississippi to Joliet, IL. Most of the individual data files were created from 1989 land cover/use data, except for the La Grange navigation pool on the Illinois River. Due to high water conditions present in 1989, 1991 aerial photography and land cover/use data were used to create the La Grange data set.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），基于1:15000比例尺的彩色红外航空相片，为密西西比河上游系统（Upper Mississippi River System, UMRS）构建了高分辨率土地覆盖/利用数据集。该数据集已被用于生成多种衍生产品，其中一款专用数据集用于水生区域分类。1989年与1991年的水生区域数据集构建流程如下：首先将现有土地覆盖/利用数据归并为陆地-水域二分数据集，随后对被归类为水域的区域内的航空影像进行重新解译，以明确水生区域的类型。本数据集的覆盖范围为明尼苏达州明尼阿波利斯至伊利诺伊州开罗的密西西比河上游河段，以及伊利诺伊河从其与密西西比河汇流处至伊利诺伊州乔利埃特的河段。除伊利诺伊河上的拉格兰奇通航池（La Grange navigation pool）外，绝大多数单个数据文件均基于1989年的土地覆盖/利用数据生成。由于1989年遭遇高水位工况，拉格兰奇数据集是通过1991年的航空影像及土地覆盖/利用数据构建而成。