Ground Truth Material
This page presents material relevant to ground truth analysis. Where possible, the masked maps were used as the source of GIS data. In some cases, a water body was large enough to have been masked out, as with lakes and reservoirs. Then, we used the unmasked maps. I do not indicate which water bodies were taken from unmasked maps. The preliminary reports are given to show how much we considered the problems and possible shortcomings. Presenting them here is an attempt at honest communication. Problems mentioned in the preliminary reports were largely solved before writing the main paper.
CATFISH PONDS: This link goes to an Excel file in which the location and size of various catfish ponds is recorded along with the GIS results. This link goes to a preliminary report from Mike Polioudakis.
ALABAMA RECREATION LAKES: This link goes to a list of state recreation lakes taken from the website of the State of Alabama. From this list we chose lakes that had a reliable location and reliable data on size. We compared the data given by the state of Alabama with our results from GIS work. The results are in an Excel file in this link. This link goes to a preliminary report.
ALABAMA RESORVOIRS: This link goes to a list of state reservoirs taken from the website of the State of Alabama. From this list we chose reservoirs that had a reliable location and reliable data on size. We compared the data given by the state of Alabama with our results from GIS work. We had to eliminate many reservoirs because they straddled the state line (usually with Georgia or Tennessee). Final data is in the original paper. This link goes to an Excel file of data. This link goes to a preliminary report.
FEDERAL NRCS PL 566 DAMS: The National Resource Conservation Service maintains a series of small dams and impoundments, mostly in northwestern Alabama. Perry Oakes of the NRCS kindly allowed us access to the schematic diagrams for these dams-with-impoundments. From these schematics, Nathan Campbell was able to locate the dams and to estimate the average size of the impoundment behind the dam. We compared the dams for which we could get reliable estimates of impoundment size under various conditions with the GIS data. The results are summarized in an Excel file that can be reached through this link. This link goes to a preliminary report.
LEE COUNTY. From all the rastars of Lee County, we generated two lists of random points: rastars in water and rastars not in water. Results from the rastars not in water have been mentioned in the main paper, or in comments to reviewers, and are not further mentioned here. For the random rastars in water, Nathan Campbell drove to each point in Lee County to see: if that point was water or not; if it was water, to estimate the size of water in that location; and, if it was not water, to describe what it was, such as “parking lot”. The results are summarized in an Excel file that is accessible through this link. In that file, the color yellow indicates “no access”; green indicates “found”; blue indicates a duplicate; and red indicates “not found”. This link goes to a preliminary report.
Nathan Campbell took pictures of most sites in Lee County where he found water. Some sites could be evaluated for the presence and size of a water body but were not easily accessible for taking a picture, as for example a site was on private land and blocked by a fence. The photos are available through links 4 through 275. The number of the photo corresponds to the number of the pond in the Excel file.