Physical Sciences and Mathematics Commons^™

Historical Water-Quality Data For The High Plains Regional Ground-Water Study Area In Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, And Wyoming, 1930–98, David W. Litke

Publications of the US Geological Survey

The High Plains aquifer underlies 174,000 square miles in parts of eight States and includes eight primary hydrogeologic units, including the well-known Ogallala Formation. The High Plains aquifer is an important resource, providing water for 27 percent of the Nation’s irrigated agricul¬tural lands in an otherwise dry landscape. Since the 1980’s there has been concern over the sustainability of the aquifer due to water-level declines caused by substantial pumping. Water quality of the aquifer is a more recent concern. As part of the U.S. Geological Survey’s National Water-Quality Assessment Program, historical water-quality data have been gathered for the High Plains …

At-Satellite Reflectance: A First Order Normalization Of Landsat 7 Etm+ Images, Chengquan Huang, Limin Yang, Collin Homer, Bruce K. Wylie, James E. Vogelmann, Thomas Defelice

Publications of the US Geological Survey

Regional Landsat applications often rely on clear and near cloud-free images. With the spectral value being represented by digital number (DN), however, such images contain substantial noises. A significant proportion of such noises can be normalized by converting the DN to at-satellite reflectance value. Being physically based and ready to automate, the conversion method can serve as a first order normalization of Landsat 7 images, making it possible to derive land surface information from such images more consistently.

Modeling Reptile And Amphibian Range Distributions From Species Occurrences And Landscape Variables, Geoffrey M. Henebry, Brian C. Putz, James W. Merchant

Publications of the US Geological Survey

An international symposium in October 1999 demonstrated the state of the art in modeling species occurrences (Scott et al. 2001). One clear message from the symposium was the broad diversity of approaches that constitute the state of the art. No single method excels, largely because of the very particular and local nature of the problem. Organisms both influence and respond to their local environment; thus, the same species may key in on different resources in different landscapes. Furthermore, modeling methods vary widely in their "transparency," which can inhibit transportability or robustness.
In order to provide an analytical modeling framework that …

A Strategy For Estimating Tree Canopy Density Using Landsat 7 Etm+ And High Resolution Images Over Large Areas, C. Huang, Limin Yang, Bruce K. Wylie, Collin Homer

Publications of the US Geological Survey

INTRODUCTION

The Multi-Resolution Land Characteristics (MRLC) consortium was initiated in early 1990s to address the need for consistently developed national and regional land cover data (Loveland and Shaw, 1996). Through this consortium, a 1992-vintage National Land Cover Dataset (NLCD) was developed for the conterminous United States (Vogelmann et al., 2001), and a second generation National Land Cover Dataset (NLCD 2000) will be developed using 2000-vintage Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images and ancillary data. The 2000 NLCD will consist of a suite of data layers relevant to many applications, including a tree canopy density layer describing percentage of …

Citizen Knowledge And Perception Of Black-Tailed Prairie Dog Management, Natalie R. Sexton, Ayeisha Brinson, Phadrea D. Ponds, Kurt Cline, Berton L. Lamb

Publications of the US Geological Survey

What do citizens know about black-tailed prairie dogs, and where do they get their information? When management decisions need to be made regarding an animal such as the black-tailed prairie dog, an understanding of the species and its relationship to humans is necessary. This includes knowing the biology of the animal, where it lives, and how it interacts with other animals. But it is equally important for those making decisions about the species to understand citizens’ knowledge and perceptions so managers can effectively communicate with the public and help the public participate in planning and decision making activities. Unfortunately, what …