Jackson Cothren

Stereo analysis, DEM extraction and orthorectification of CORONA satellite imagery: archaeological applications from the Near East

CORONA satellite imagery, preserving an account of the earths surface from 40 years ago, is a most important archaeological survey tool and we have often sung its praises. Here the authors use new procedures to extend the competence and revelations of CORONA even further. Stereo pairs derived from images taken from fore and aft of the satellite give three dimensional images of landscapes and even individual sites. Techniques of modelling and rectification restore the sites to their original shape without recourse to survey on the ground – in many cases no longer possible since the sites have been buried, inundated or erased. The ingenuity shown here indicates that results from CORONA are only going to get better.

Accelerating SIFT on parallel architectures

SIFT is a widely-used algorithm that extracts features from images; using it to extract information from hundreds of terabytes of aerial and satellite photographs requires paral-lelization in order to be feasible. We explore accelerating an existing serial SIFT implementation with OpenMP parallelization and GPU execution.

Extending a Natural Language Interface with Geospatial Queries

In this installation of architectural perspectives, we describe an extension of a menu-based natural language interface (MBNLI) to support geospatial queries. Our extension makes it easier for application analysts and even inexperienced users to phrase complex queries without knowing the relational database query language SQL, database schemas (table structures), spatial operators, or spatial indexes.

Geospatial and Temporal Patterns of Preparatory Conduct among American Terrorists

Although terrorism research has made significant strides during the past five years, even the most rudimentary patterns of terrorists’ behaviors remain unknown to scholars and analysts. In the current study, we analyze spatial and temporal patterns of criminal acts related to a variety of American terrorism cases and attempt to provide insight into these questions: 1) where do terrorists live in relation to the targets they select, 2) do they plan and prepare their acts of terrorism relatively close to the target or do they intentionally conduct these activities far from the target, 3) what types of preparatory activities do the terrorists usually commit, and 4) how long is this planning process and does it vary by group type? Results from this study allow us to draw the following conclusions. First, about one‐half of terrorists both reside and prepare for their terrorist incidents within a thirty‐mile radius of their residences, although the radius of activity shows significant variation based on group type. Second, the temporal dimensions of terrorist activity reveal that terrorist planning and preparation is more complex than originally anticipated. Finally, while the interaction between time and space has not been addressed, our initial impressions of our temporal and spatial data suggest a scenario much like a predator closing in on a prey—as the planned incident draws nearer temporally, the spatial events also draw nearer to the target location. What our initial data have not revealed is whether these events are temporally and spatially sequenced in such a way that they can be of predictive value. Our study suggests the importance of further research in specific areas, including the identification of the prevalent types of preparatory and ancillary crimes terrorists commit in preparation for a terrorist incident, the identification of patterns of preparatory criminal activity that might either alert law enforcement officials to the existence of terrorist group activities or identify characteristic preparatory offenses, temporal sequencing of preparatory acts in relation to completed acts of terrorism, and geographic patterns to assist in threat assessment.

The CORONA Atlas Project: Orthorectification of CORONA Satellite Imagery and Regional-Scale Archaeological Exploration in the Near East

Declassified, Cold War-era CORONA satellite images have proven to be a critical tool in archaeology of the Near East and elsewhere, primarily because they preserve a picture of sites and landscapes that predates recent agricultural, industrial and urban development. However, unprocessed CORONA images contain extreme spatial distortions caused by a cross-path panoramic scanning system, and the absence of detailed orientation and camera information makes correction of these errors highly challenging, resulting in small-scale, piecemeal application of this resource. This chapter overviews our methods for efficient orthorectification of KH-4A and KH-4B CORONA imagery and our development of a freely accessible online database for viewing and distribution of corrected images. We also highlight our efforts to deploy regional-scale CORONA coverage to facilitate the discovery and documentation of archaeological landscapes from across the Northern Fertile Crescent.

RESEARCH ARTICLE: Offshore Wind Turbine Visibility and Visual Impact Threshold Distances

Potential visual impact on coastal lands has emerged as a major concern in the development of offshore wind facilities in the United States and Europe. Optimal siting of offshore facilities requires accurate knowledge of the relationship between distance and the visibility of wind turbines. Past assessments of offshore wind turbine visibility were based on smaller turbines and facilities in use at the time and underestimate visibility for current projects, which use more and larger larger turbines. This study is a preliminary assessment of the visibility of offshore wind facilities in the United Kingdom. Study objectives included identifying the maximum distances the facilities could be seen in both daytime and nighttime views and assessing the effect of distance on visual contrasts associated with the facilities. Results showed that small to moderately sized facilities were visible to the unaided eye at distances greater than 42 km [26 miles (mi)], with turbine blade movement visible up to 39 km (24 mi). At night, aerial hazard navigation lighting was visible at distances greater than 39 km (24 mi). The observed wind facilities were judged to be a major focus of visual attention at distances up to 16 km (10 mi), were noticeable to casual observers at distances of almost 29 km (18 mi), and were visible with extended or concentrated viewing at distances beyond 40 km (25 mi).

Integration of Water Resource Models with Fayetteville Shale Decision Support and Information System

Significant issues can arise with the timing, location, and volume of surface water withdrawals associated with hydraulic fracturing of gas shale reservoirs as impacted watersheds may be sensitive, especially in drought years, during low flow periods, or during periods of the year when activities such as irrigation place additional demands on the surface supply of water. Significant energy production and associated water withdrawals may have a cumulative impact to watersheds over the short-term. Hence, hydraulic fracturing based on water withdrawal could potentially create shifts in the timing and magnitude of low or high flow events or change the magnitude of river flow at daily, monthly, seasonal, or yearly time scales. These changes in flow regimes can result in dramatically altered river systems. Currently little is known about the impact of fracturing on stream flow behavior. Within this context the objective of this study is to assess the impact of the hydraulic fracturing on the water balance of the Fayetteville Shale play area and examine the potential impacts of hydraulic fracturing on river flow regime at subbasin scale. This project addressed that need with four unique but integrated research and development efforts: 1) Evaluate the predictive reliability of the Soil and Water Assessment Tool (SWAT) model based at a variety of scales (Task/Section 3.5). The Soil and Water Assessment Tool (SWAT) model was used to simulate the across-scale water balance and the respective impact of hydraulic fracturing. A second hypothetical scenario was designed to assess the current and future impacts of water withdrawals for hydraulic fracturing on the flow regime and on the environmental flow components (EFCs) of the river. The shifting of these components, which present critical elements to water supply and water quality, could influence the ecological dynamics of river systems. For this purpose, we combined the use of SWAT model and Richter et al.’s (1996) methodology to assess the shifting and alteration of the flow regime within the river and streams of the study area. 2) Evaluate the effect of measurable land use changes related to gas development (well-pad placement, access road completion, etc.) on surface water flow in the region (Task/Section 3.7). Results showed that since the upsurge in shale-gas related activities in the Fayetteville Shale Play (between 2006 and 2010), shale-gas related infrastructure in the region have increase by 78%. This change in land-cover in comparison with other land-cover classes such as forest, urban, pasture, agricultural and water indicates the highest rate of change in any land-cover category for the study period. A Soil and Water Assessment Tool (SWAT) flow model of the Little Red River watershed simulated from 2000 to 2009 showed a 10% increase in storm water runoff. A forecast scenario based on the assumption that 2010 land-cover does not see any significant change over the forecast period (2010 to 2020) also showed a 10% increase in storm water runoff. Further analyses showed that this change in the stream-flow regime for the forecast period is attributable to the increase in land-cover as introduced by the shale-gas infrastructure. 3) Upgrade the Fayetteville Shale Information System to include information on watershed status. (Tasks/Sections 2.1 and 2.2). This development occurred early in the project period, and technological improvements in web-map API’s have made it possible to further improve the map. The current sites (http://lingo.cast.uark.edu) is available but is currently being upgraded to a more modern interface and robust mapping engine using funds outside this project. 4) Incorporate the methodologies developed in Tasks/Sections 3.5 and 3.7 into a Spatial Decision Support System for use by regulatory agencies and producers in the play. The resulting system is available at http://fayshale.cast.uark.edu and is under review the Arkansas Natural Resources Commission.

Yearly Extraction of Central America's Land Cover for Carbon Flux Monitoring

Ideal remote sensor land cover extraction for national to regional carbon flux monitoring constitutes highly accurate change detection on an annual basis, a challenge magnified in the cloud-occluded tropics. Focusing on seven Central American countries from Belize to Panama, this study tested the feasibility of yearly land cover extraction from MODIS surface reflectance composites, ancillary land cover maps, and country-produced reference polygons. GIS models were created to automate the country-specific process of generating annual input tables for a greenhouse gas inventory tool. MODIS-favorable results in a six-category schema suggest that improvements may depend on international reference data warehousing and interoperability.

Information Rich GIS Dissemination in Disconnected Environments

Information-rich maps are today rendered from powerful back-end servers. Unfortunately, there may be circumstances in which access to such Internet-resident web services is infeasible or unreliable. These disconnected environments can theoretically occur during major power outages, malicious attacks on communications infrastructure, natural disasters, or in remote operating environments. One might also envision applications in which a disconnected service is preferred over Internet-resident services, such as when the local internet service is overloaded with traffic, making communication though it difficult. To this end, this article presents a software stack (a map stack) that can serve GIS information from low power embedded nodes. The system combines a spatially enabled SQL database, location-based routing, and multi-scale map rendering to serve information-rich GIS data on common hand-held devices at minimal energy consumption. The maps are rendered on browsers on off-the-shelf mobile devices such as smart phones and tablets. The system also provides a crowd sourced capability where end users can annotate maps with up-to-date information on the scene of the natural disaster. We have prototyped a fully functional map stack on a battery powered Gumstix Overo air platform. We show that the map stack is a highly extensible platform that provides low latency, and low energy dissemination of maps during a natural disaster.

Accelerating SIFT on hybrid clusters

We describe an approach to parallelizing SIFT and other scale-space-based feature transformation algorithms. By partitioning the workload in a novel fashion, our approach can take advantage of all forms of parallelism: the shared-memory parallelism of threaded programming, the distributed-memory approach of cluster programming, and GPU-based acceleration. Also described is an implementation of this approach called SOHC, or SIFT on hybrid clusters, which can take advantage of hybrid clusters to accelerate the transformation of arbitrarily large images into sets of features. SOHC is both portable and scalable: it can run on systems ranging from a desktop without any GPU hardware, to a cluster of multi-GPU nodes, with the only difference being time to complete the extraction. It is the only implementation of SIFT capable of operating directly (i.e. without dropping features at tile boundaries) on gigapixel-sized images often encountered in geospatial applications.