Search USGS⌕ Search

SEARCH · Search USGS

Results for “Data”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,603 records · Page 89Linked to original sources
USGS2013

Influence of multi-source and multi-temporal remotely sensed and ancillary data on the accuracy of random forest classification of wetlands in northern Minnesota

Wetland mapping at the landscape scale using remotely sensed data requires both affordable data and an efficient accurate classification method. Random forest classification offers several advantages over traditional land cover classification techniques, including a bootstrapping technique to generate robust estimations of outliers in the training data, as well as the capability of measuring classification confidence. Though the random forest classifier can generate complex decision trees with a multitude of input data and still not run a high risk of over fitting, there is a great need to reduce computational and operational costs by including only key input data sets without sacrificing a significant level of accuracy. Our main questions for this study site in Northern Minnesota were: (1) how does classification accuracy and confidence of mapping wetlands compare using different remote sensing platforms and sets of input data; (2) what are the key input variables for accurate differentiation of upland, water, and wetlands, including wetland type; and (3) which datasets and seasonal imagery yield the best accuracy for wetland classification. Our results show the key input variables include terrain (elevation and curvature) and soils descriptors (hydric), along with an assortment of remotely sensed data collected in the spring (satellite visible, near infrared, and thermal bands; satellite normalized vegetation index and Tasseled Cap greenness and wetness; and horizontal-horizontal (HH) and horizontal-vertical (HV) polarization using L-band satellite radar). We undertook this exploratory analysis to inform decisions by natural resource managers charged with monitoring wetland ecosystems and to aid in designing a system for consistent operational mapping of wetlands across landscapes similar to those found in Northern Minnesota.

Minnesota↗
USGS2023

Recharge estimation approach in a data-scarce semi-arid region, Northern Ethiopian Rift Valley

Sustainable management of groundwater resources highly relies on the accurate estimation of recharge. However, accurate recharge estimation is a challenge, especially in data-scarce regions, as the existing models are data-intensive and require extensive parameterization. This study developed a process-based hydrologic model combining local and remotely sensed data for characterizing recharge in data-limited regions using a Basin Characterization Model (BCM). This study was conducted in Raya and Kobo Valleys, a semi-arid region in Northern Ethiopia, considering both the structural basin and the surrounding mountainous recharge areas. Climatic Research Unit monthly datasets for 1991 to 2020 and WaPOR actual evapotranspiration data were used. The model results show that the average annual recharge and surface runoff from 1991 to 2020 were 73 mm and 167 mm, respectively, with a substantial portion contributed along the front of the mountainous parts of the study area. The mountainous recharge occurred along and above the valleys as mountain-block and mountain-front recharge. The long-term estimates of the monthly recharge time series indicated that the water balance components follow the temporal pattern of rainfall amount. However, the relation of recharge to precipitation was nonlinearly related, showing the episodic nature of recharge in semi-arid regions. This study informed the spatial and temporal distribution of recharge and runoff hydrologic variables at fine spatial scales for each grid cell, allowing results to be summarized for various planning units, including farmlands. One third of the precipitation in the drainage basin becomes recharge and runoff, while the remaining is lost through evapotranspiration. The current study’s findings are vital for developing plans for sustainable management of water resources in semi-arid regions. Also, monthly groundwater withdrawals for agriculture should be regulated in relation to spatial and temporal recharge patterns. We conclude that combining scarce local data with global datasets and tools is a useful approach for estimating recharge to manage groundwater resources in data-scarce regions.

Kobo Valley, Riya Valley↗
USGS2021

Beyond streamflow: Call for a national data repository of streamflow presence for streams and rivers in the United States

Observations of the presence or absence of surface water in streams are useful for characterizing streamflow permanence, which includes the frequency, duration, and spatial extent of surface flow in streams and rivers. Such data are particularly valuable for headwater streams, which comprise the vast majority of channel length in stream networks, are often non-perennial, and are frequently the most data deficient. Datasets of surface water presence exist across multiple data collection groups in the United States but are not well aligned for easy integration. Given the value of these data, a unified approach for organizing information on surface water presence and absence collected by diverse surveys would facilitate more effective and broad application of these data and address the gap in streamflow data in headwaters. In this paper, we highlight the numerous existing datasets on surface water presence in headwater streams, including recently developed crowdsourcing approaches. We identify the challenges of integrating multiple surface water presence/absence datasets that include differences in the definitions and categories of streamflow status, data collection method, spatial and temporal resolution, and accuracy of geographic location. Finally, we provide a list of critical and useful components that could be used to integrate different streamflow permanence datasets.

Water↗
USGS2014

Detecting emergence, growth, and senescence of wetland vegetation with polarimetric synthetic aperture radar (SAR) data

Wetlands provide ecosystem goods and services vitally important to humans. Land managers and policymakers working to conserve wetlands require regularly updated information on the statuses of wetlands across the landscape. However, wetlands are challenging to map remotely with high accuracy and consistency. We investigated the use of multitemporal polarimetric synthetic aperture radar (SAR) data acquired with Canada’s Radarsat-2 system to track within-season changes in wetland vegetation and surface water. We speculated, a priori , how temporal and morphological traits of different types of wetland vegetation should respond over a growing season with respect to four energy-scattering mechanisms. We used ground-based monitoring data and other ancillary information to assess the limits and consistency of the SAR data for tracking seasonal changes in wetlands. We found the traits of different types of vertical emergent wetland vegetation were detected well with the SAR data and corresponded with our anticipated backscatter responses. We also found using data from Landsat’s optical/infrared sensors in conjunction with SAR data helped remove confusion of wetland features with upland grasslands. These results suggest SAR data can provide useful monitoring information on the statuses of wetlands over time.

Water↗
USGS2014

Assessing effects of variation in global climate data sets on spatial predictions from climate envelope models

Climate change poses new challenges for natural resource managers. Predictive modeling of species–environment relationships using climate envelope models can enhance our understanding of climate change effects on biodiversity, assist in assessment of invasion risk by exotic organisms, and inform life-history understanding of individual species. While increasing interest has focused on the role of uncertainty in future conditions on model predictions, models also may be sensitive to the initial conditions on which they are trained. Although climate envelope models are usually trained using data on contemporary climate, we lack systematic comparisons of model performance and predictions across alternative climate data sets available for model training. Here, we seek to fill that gap by comparing variability in predictions between two contemporary climate data sets to variability in spatial predictions among three alternative projections of future climate. Overall, correlations between monthly temperature and precipitation variables were very high for both contemporary and future data. Model performance varied across algorithms, but not between two alternative contemporary climate data sets. Spatial predictions varied more among alternative general-circulation models describing future climate conditions than between contemporary climate data sets. However, we did find that climate envelope models with low Cohen's kappa scores made more discrepant spatial predictions between climate data sets for the contemporary period than did models with high Cohen's kappa scores. We suggest conservation planners evaluate multiple performance metrics and be aware of the importance of differences in initial conditions for spatial predictions from climate envelope models.

Journal of Fish and Wildlife Management↗
USGS2010

Ocean and coastal data management

We introduce data management concepts, including what we mean by "data" and its "management," sources of data, interoperability, and data geometry. We then discuss various components of a data management system. Finally, we summarize some existing ocean and coastal data management efforts. We make specific recommendations throughout the paper. We are generally optimistic that ocean and coastal data management is an interesting and solvable challenge that will provide great benefit to society.

Conference Paper↗
USGS2017

Capturing change: the duality of time-lapse imagery to acquire data and depict ecological dynamics

We investigate the scientific and communicative value of time-lapse imagery by exploring applications for data collection and visualization. Time-lapse imagery has a myriad of possible applications to study and depict ecosystems and can operate at unique temporal and spatial scales to bridge the gap between large-scale satellite imagery projects and observational field research. Time-lapse data sequences, linking time-lapse imagery with data visualization, have the ability to make data come alive for a wider audience by connecting abstract numbers to images that root data in time and place. Utilizing imagery from the Platte Basin Timelapse Project, water inundation and vegetation phenology metrics are quantified via image analysis and then paired with passive monitoring data, including streamflow and water chemistry. Dynamic and interactive time-lapse data sequences elucidate the visible and invisible ecological dynamics of a significantly altered yet internationally important river system in central Nebraska.

Nebraska↗
USGS2001

Access to bird population data

Access to bird population data is critical for effective conservation planning and implementation. Although a tremendous volume of baseline data exists, it is often diffusely distributed and inaccessible to the resource manager and decision maker. A mechanism that facilitates assembly, documentation and delivery of avian data in a user-friendly manner is needed in order to integrate bird-related information resources across agencies and organizations. To address this fundamental need, the National Biological Information Infrastructure (NBII), in partnership with the U.S. Geological Survey's Patuxent Wildlife Research Center and the U.S. Fish and Wildlife Service, is developing a web-based interactive system that will focus on access to bird population and habitat data used in bird management and conservation. This system, known as the NBII Bird Conservation Node, will support planning and evaluation of bird conservation activities within the context of the North American Bird Conservation Initiative (NABCI), a framework for collaboration among organizations interested in bird conservation across North America. Initial development of the NBII Bird Conservation Node will focus on creating a prototype mapping application that will provide interactive access to data from the North American Breeding Bird Survey, the Colonial Waterbird Survey, the Breeding Waterfowl Population and Habitat Survey, and the Atlantic Flyway Mid-winter Waterfowl Survey. This prototype mapping application, to be available on-line at http://www.nbii.gov by Sep 2001, will lay the foundation for establishment of a Migratory Bird Data Center at Patuxent Wildlife Research Center, and will provide an opportunity for linking to and establishing partnerships with other sources of bird population and habitat data available over the Internet.

Book chapter↗
USGS2002

Using Christmas Bird Count data in analysis of population change

The scientific credibility of Christmas Bird Count (CBC) results depend on the development and implementation of appropriate methods of statistical analysis. The key to any successful analysis of CBC data is to begin with a careful review of how the limitations of the data are likely to influence the results of the analysis, then to choose methods of analysis that accommodate as much as possible the limitations of the survey. For our analyses of CBC data, we develop a flexible model for effort adjustment and use information from the data to guide the selection of the best model. We include geographic structuring to accommodate the regional variation in number of samples, use a model that allows for overdispersed poisson data appropriate for counts, and employ empirical Bayes procedures to accommodate differences in quality of information in regional summaries. This generalized linear model approach is very flexible, and can be applied to a variety of studies focused on factors influencing wintering bird populations. In particular, the model can be easily modified to contain covariates, allowing for assessment of associations between CBC counts and winter weather, disturbance, and a variety of other environmental factors. These new survey analysis methods have added value in that they provide insights into changes in survey design that can enhance the value of the information. The CBC has been extremely successful as a tool for increasing public interest in birding and bird conservation. Use of the information for bird conservation creates new demands on quality of information, and it is important to maintain a dialogue between users of the information, information needs for the analyses, and survey coordinators and participants. Our work as survey analysts emphasizes the value and limitations of existing data, and provides some indications of what features of the survey could be modified to make the survey a more reliable source of bird population data. Surveys only remain useful if they adapt to current needs, while still maintaining consistency with historical goals.

American Birds↗
USGS1984

JOINT DEVELOPMENT OF A NATIONAL 1:100,000-SCALE DIGITAL CARTOGRAPHIC DATA BASE.

The U. S. Geological Survey is beginning a major new program to create a nationwide digital cartographic data base from 1:100,000-scale maps by the end of the decade. This data base will supplement the currently available 1:2,000,000-scale national data base and the selected coverage at 1:24,000-scale. It is anticipated that the data will be useful for both the production of custom graphics and as basic input to geographic information systems. The 1:100,000-scale USGS map series was designed to facilitate automated data capture. The methodologies and procedures used in the data capture process have developed enough so that the two agencies can take advantage of the design features of the 1:100,000-scale maps and work together on complementary tasks to build a digital cartographic data base.

Conference Paper↗
USGS1987

DISTRIBUTED GROUND-WATER DATA BASE OF THE U. S. G. S.

During the past 20 years, the ground-water data base of the U. S. Geological Survey has evolved from paper files in local offices, to a national data base on a central mainframe computer, to a distributed data base on a network of 49 minicomputers throughout the United States. Users in local offices have easy, inexpensive access to the distributed data base. The distributed data base has caused some problems in data management but has increased the overall quality of the data base.

Conference Paper↗
USGS1989

Spectral analysis and filtering techniques in digital spatial data processing

A filter toolbox has been developed at the EROS Data Center, US Geological Survey, for retrieving or removing specified frequency information from two-dimensional digital spatial data. This filter toolbox provides capabilities to compute the power spectrum of a given data and to design various filters in the frequency domain. Three types of filters are available in the toolbox: point filter, line filter, and area filter. Both the point and line filters employ Gaussian-type notch filters, and the area filter includes the capabilities to perform high-pass, band-pass, low-pass, and wedge filtering techniques. These filters are applied for analyzing satellite multispectral scanner data, airborne visible and infrared imaging spectrometer (AVIRIS) data, gravity data, and the digital elevation models (DEM) data. -from Author

Photogrammetric Engineering and Remote Sensing↗
USGS1991

Use of electronic microprocessor-based instrumentation by the U.S. geological survey for hydrologic data collection

The U.S. Geological Survey is acquiring a new generation of field computers and communications software to support hydrologic data-collection at field locations. The new computer hardware and software mark the beginning of the Survey's transition from the use of electromechanical devices and paper tapes to electronic microprocessor-based instrumentation. Software is being developed for these microprocessors to facilitate the collection, conversion, and entry of data into the Survey's National Water Information System. The new automated data-collection process features several microprocessor-controlled sensors connected to a serial digital multidrop line operated by an electronic data recorder. Data are acquired from the sensors in response to instructions programmed into the data recorder by the user through small portable lap-top or hand-held computers. The portable computers, called personal field computers, also are used to extract data from the electronic recorders for transport by courier to the office computers. The Survey's alternative to manual or courier retrieval is the use of microprocessor-based remote telemetry stations. Plans have been developed to enhance the Survey's use of the Geostationary Operational Environmental Satellite telemetry by replacing the present network of direct-readout ground stations with less expensive units. Plans also provide for computer software that will support other forms of telemetry such as telephone or land-based radio.

Conference Paper↗
USGS1991

Comparison of three different methods to merge multiresolution and multispectral data: Landsat TM and SPOT panchromatic

The merging of multisensor image data is becoming a widely used procedure because of the complementary nature of various data sets. Ideally, the method used to merge data sets with high-spatial and high-spectral resolution should not distort the spectral characteristics of the high-spectral resolution data. This paper compares the results of three different methods used to merge the information contents of the Landsat Thematic Mapper (TM) and Satellite Pour l'Observation de la Terre (SPOT) panchromatic data. The comparison is based on spectral characteristics and is made using statistical, visual, and graphical analyses of the results. The three methods used to merge the information contents of the Landsat TM and SPOT panchromatic data were the Hue-Intensity-Saturation (HIS), Principal Component Analysis (PCA), and High-Pass Filter (HPF) procedures. The HIS method distorted the spectral characteristics of the data the most. The HPF method distorted the spectral characteristics the least; the distortions were minimal and difficult to detect. -Authors

Photogrammetric Engineering and Remote Sensing↗
USGS1994

Real-time data collection of scour at bridges

The record flood on the Mississippi River during the summer of 1993 provided a rare opportunity to collect data on scour of the streambed at bridges and to test data collection equipment under extreme hydraulic conditions. Detailed bathymetric and hydraulic information were collected at two bridges crossing the Mississippi River during the rising limb, near the peak, and during the recession of the flood. Bathymetric data were collected using a digital echo sounder. Three-dimensional velocities were collected using Broadband Acoustic Doppler Current Profilers (BB-ADCP) operating at 300 kilohertz (kHz), 600 kHz, and 1,200 kHz. Positioning of the data collected was measured using a range-azimuth tracking system and two global positioning systems (GPS). Although differential GPS was able to provide accurate positions and tracking information during approach- and exit-reach data collection, it was unable to maintain lock on a sufficient number of satellites when the survey vessel was under the bridge or near the piers. The range-azimuth tracking system was used to collect position and tracking information for detailed data collection near the bridge piers. These detailed data indicated local scour ranging from 3 to 8 meters and will permit a field-based evaluation of the ability of various numerical models to compute the hydraulics, depth, geometry, and time-dependent development of local scour.

Conference Paper↗
USGS2001

Hierarchical programming for data storage and visualization

Graphics software is an essential tool for interpreting, analyzing, and presenting data from multidimensional hydrodynamic models used in estuarine and coastal ocean studies. The post-processing of time-varying three-dimensional model output presents unique requirements for data visualization because of the large volume of data that can be generated and the multitude of time scales that must be examined. Such data can relate to estuarine or coastal ocean environments and come from numerical models or field instruments. One useful software tool for the display, editing, visualization, and printing of graphical data is the Gr application, written by the first author for use in U.S. Geological Survey San Francisco Bay Program. The Gr application has been made available to the public via the Internet since the year 2000. The Gr application is written in the Java (Sun Microsystems, Nov. 29, 2001) programming language and uses the Extensible Markup Language standard for hierarchical data storage. Gr presents a hierarchy of objects to the user that can be edited using a common interface. Java's object-oriented capabilities allow Gr to treat data, graphics, and tools equally and to save them all to a single XML file.

Conference Paper↗
USGS2002

Comparability and accuracy of fluvial-sediment data - A view from the U.S. Geological Survey

The quality of historical fluvial-sediment data cannot be taken for granted, based on a review of upper Colorado River basin suspended-sediment discharges, and on an evaluation of the reliability of Total Suspended Solids (TSS) data. Additionally, the quality of future fluvial-sediment data are not assured. Sediment-surrogate technologies, including those that operate on acoustic, laser, bulk optic, digital optic, or pressure differential principles, are being used with increasing frequency to measure in-stream and (or) laboratory fluvial-sediment characteristics. Data from sediment-surrogate technologies may yield results that differ significantly from those obtained by traditional methods for the same sedimentary conditions. Development of national sediment data-quality criteria and rigorous comparisons of data derived from sediment-surrogate technologies to those obtained by traditional techniques will minimize the potential for future fluvial-sediment data-quality concerns.

Conference Paper↗
USGS1969

Hydrogeologic data for the southwestern coastal river basins, Connecticut

This report presents hydrologic and geologic data collected by the U.S. Geological Survey during an investigation of water resources in the southwestern coastal river basins of Connecticut in cooperation with the Connecticut Water Resources Commission. These basins occupy about 394 square miles in Connecticut and 46 square miles in New York, including the towns of Greenwich, Stamford, Darien, New Canaan, Norwalk, Wilton, Westport, Weston, Fairfield, Easton, and Bridgeport and parts of Danbury, Ridgefield, Redding, Bethel, Newtown, Trumbull, Monroe, Shelton, and Stratford. A companion interpretive report evaluating the water resources of the basins will be published as Connecticut Water Resources Bulletin No. 17. The data on the following pages serve to document and supplement that report and should be especially useful in planning the development of water resources at specific localities. Data were collected as part of this investigation during the period July 1963 through November 1966. Streamflow records from continuous-record gaging stations in the basins have been published annually along with data from other parts of the State in a series of U.S. Geological Survey reports entitled "Surface Water Records of Connecticut." Water-level measurements in wells throughout the State from 1960 through 1966, including most of those made as part of this investigation, are published in Connecticut Water Resources Bulletins No. 7 and No. 13. Most other data collected during this investigation are tabulated on the following pages. Included are some well records and chemical analyses of water samples collected prior to July 1963 and not previously published. The locations of sites at which data were collected are shown on plate A in the pocket at the back of the report. Data presented, unless otherwise noted, were collected by U.S. Geological Survey personnel.

Connecticut↗