Geology topics

Daniel R. Steinwand

Publications and source records attributed to Daniel R. Steinwand.

10 recordsLinked to original sources

USGS2015

A landsat data tiling and compositing approach optimized for change detection in the conterminous United States

Annual disturbance maps are produced by the LANDFIRE program across the conterminous United States (CONUS). Existing LANDFIRE disturbance data from 1999 to 2010 are available and current efforts will produce disturbance data through 2012. A tiling and compositing approach was developed to produce bi-annual images optimized for change detection. A tiled grid of 10,000 × 10,000 30 m pixels was defined for CONUS and adjusted to consolidate smaller tiles along national borders, resulting in 98 non-overlapping tiles. Data from Landsat-5,-7, and -8 were re-projected to the tile extents, masked to remove clouds, shadows, water, and snow/ice, then composited using a cosine similarity approach. The resultant images were used in a change detection algorithm to determine areas of vegetation change. This approach enabled more efficient processing compared to using single Landsat scenes, by taking advantage of overlap between adjacent paths, and allowed an automated system to be developed for the entire process.

Photogrammetric Engineering and Remote Sensing↗

USGS2012

A program for handling map projections of small-scale geospatial raster data

Scientists routinely accomplish small-scale geospatial modeling using raster datasets of global extent. Such use often requires the projection of global raster datasets onto a map or the reprojection from a given map projection associated with a dataset. The distortion characteristics of these projection transformations can have significant effects on modeling results. Distortions associated with the reprojection of global data are generally greater than distortions associated with reprojections of larger-scale, localized areas. The accuracy of areas in projected raster datasets of global extent is dependent on spatial resolution. To address these problems of projection and the associated resampling that accompanies it, methods for framing the transformation space, direct point-to-point transformations rather than gridded transformation spaces, a solution to the wrap-around problem, and an approach to alternative resampling methods are presented. The implementations of these methods are provided in an open-source software package called MapImage (or mapIMG , for short), which is designed to function on a variety of computer architectures.

Cartographic Perspectives↗

USGS2003

Geowall: Investigations into low-cost stereo display technologies

Recently, the combination of new projection technology, fast, low-cost graphics cards, and Linux-powered personal computers has made it possible to provide a stereoprojection and stereoviewing system that is much more affordable than previous commercial solutions. These Geowall systems are low-cost visualization systems built with commodity off-the-shelf components, run on open-source (and other) operating systems, and using open-source applications software. In short, they are "Beowulf-class" visualization systems that provide a cost-effective way for the U. S. Geological Survey to broaden participation in the visualization community and view stereoimagery and three-dimensional models2.

Open-File Report↗

USGS2003

Extending Beowulf Clusters

Beowulf clusters can provide a cost-effective way to compute numerical models and process large amounts of remote sensing image data. Usually a Beowulf cluster is designed to accomplish a specific set of processing goals, and processing is very efficient when the problem remains inside the constraints of the original design. There are cases, however, when one might wish to compute a problem that is beyond the capacity of the local Beowulf system. In these cases, spreading the problem to multiple clusters or to other machines on the network may provide a cost-effective solution.

Open-File Report↗

USGS2003

Processing large remote sensing image data sets on Beowulf clusters

High-performance computing is often concerned with the speed at which floating- point calculations can be performed. The architectures of many parallel computers and/or their network topologies are based on these investigations. Often, benchmarks resulting from these investigations are compiled with little regard to how a large dataset would move about in these systems. This part of the Beowulf study addresses that concern by looking at specific applications software and system-level modifications. Applications include an implementation of a smoothing filter for time-series data, a parallel implementation of the decision tree algorithm used in the Landcover Characterization project, a parallel Kriging algorithm used to fit point data collected in the field on invasive species to a regular grid, and modifications to the Beowulf project's resampling algorithm to handle larger, higher resolution datasets at a national scale. Systems-level investigations include a feasibility study on Flat Neighborhood Networks and modifications of that concept with Parallel File Systems.

Open-File Report↗

USGS2003

Extending the Beowulf Cluster to the Desktop

Existing Beowulf clusters are normally limited to the actual number of compute nodes physically connected to the cluster's network switch. At some point, it may become necessary to extend the size of the cluster beyond the capacity of the switch. By using existing computers on a campus network, one can extend the computing power of the cluster by including these machines during times they would normally be idle. We have done a survey of methods for extending clusters and devised a parallel solution to a computationally complex all-possible-regressions algorithm and tested it by using idle computing power on the campus network.

Open-File Report↗

USGS1995

Map projections for global and continental data sets and an analysis of pixel distortion caused by reprojection

In global change studies the effects of map projection properties on data quality are apparent, and the choice of projection is significant. To aid compilers of global and continental data sets, six equal-area projections were chosen: the interrupted Goode Homolosine, the interrupted Mollweide, the Wagner IV, and the Wagner VII for global maps; the Lambert Azimuthal Equal-Area for hemisphere maps; and the Oblated Equal-Area and the Lambert Azimuthal Equal-Area for continental maps. Distortions in small-scale maps caused by reprojection, and the additional distortions incurred when reprojecting raster images, were quantified and graphically depicted. For raster images, the errors caused by the usual resampling methods (pixel brightness level interpolation) were responsible for much of the additional error where the local resolution and scale change were the greatest.

Photogrammetric Engineering and Remote Sensing↗

USGS1993

Processing techniques for global land 1-km AVHRR data

The U.S. Geological Survey's (USGS) Earth Resources Observation Systems (EROS) Data Center (EDC) in cooperation with several international science organizations has developed techniques for processing daily Advanced Very High Resolution Radiometer (AVHRR) 1-km data of the entire global land surface. These techniques include orbital stitching, geometric rectification, radiometric calibration, and atmospheric correction. An orbital stitching algorithm was developed to combine consecutive observations acquired along an orbit by ground receiving stations into contiguous half-orbital segments. The geometric rectification process uses an AVHRR satellite model that contains modules for forward mapping, forward terrain correction, and inverse mapping with terrain correction. The correction is accomplished by using the hydrologic features coastlines and lakes from the Digital Chart of the World. These features are rasterized into the satellite projection and are matched to the AVHRR imagery using binary edge correlation techniques. The resulting coefficients are related to six attitude correction parameters: roll, roll rate, pitch, pitch rate, yaw, and altitude. The image can then be precision corrected to a variety of map projections and user-selected image frames. Because the AVHRR lacks onboard calibration for the optical wavelengths, a series of time-variant calibration coefficients derived from vicarious calibration methods and are used to model the degradation profile of the instruments. Reducing atmospheric effects on AVHRR data is important. A method has been develop that will remove the effects of molecular scattering and absorption from clear sky observations, using climatological measurements of ozone. Other methods to remove the effects of water vapor and aerosols are being investigated.

Pecora 12 Symposium↗

USGS1993

An earth remote sensing satellite- 1 Synthetic Aperture Radar Mosaic of the Tanana River Basin in Alaska

Because the pixel location in a line of Synthetic Aperture Radar (SAR) image data is directly related to the distance the pixel is from the radar, terrain elevations cause large displacement errors in the geo-referenced location of the pixel. This is especially true for radar systems with small angles between the nadir and look vectors. Thus, to geo-register a SAR image accurately, the terrain of the area must be taken into account. (Curlander et al., 1987; Kwok et al., 1987, Schreier et al., 1990; Wivell et al., 1992). As part of the 1992 National Aeronautics and Space Administration's Earth Observing System Version 0 activities, a prototype SAR geocod-. ing and terrain correction system was developed at the US. Geological Survey's (USGS) E~os Data Center (EDC) in Sioux Falls, South Dakota. Using this system with 3-arc-second digital elevation models (DEMs) mosaicked at the ED^ Alaska Field Office, 21 ERS-I s.4~ scenes acquired at the Alaska SAR Facility were automatically geocoded, terrain corrected, and mosaicked. The geo-registered scenes were mosaicked using a simple concatenation.

Photogrammetric Engineering and Remote Sensing↗

USGS1992

Evaluation of terrain models for the geocoding and terrain correction, of synthetic aperture radar (SAR) images

The variability of the resolutions and the presence of artifacts cause inaccurate correction of the terrain-induced geometric distortions in synthetic-aperture radar (SAR) images. To quantify the effects of these inaccuracies on SAR terrain correction, corrections of a Seasat SAR image were performed using a 1 degrees US Geological Survey (USGS) terrain model, a 7.5-min USGS terrain model, and a terrain model derived from stereoimagery acquired from SPOT. Geometric verifications of the corrected imagery showed that the resolution of the 1 degrees terrain model is not adequate to resolve many features in the Seasat image. Geometric verifications of images corrected with the two higher resolution terrain models showed localized errors as large as 52 m for mountain peaks. However, comparison of data corrected with those models shows that both produce results that differ by less than the resolution of either of them. Periodic artifacts observed in the terrain models translated to ground range differences of 18 m, which are well below the resolution of the SAR imagery.

IEEE Transactions on Geoscience and Remote Sensing↗