For convenience, they almost always choose a grid which is evenly spaced in both latitude and longitude over the surface of the globe. It is very common for Earth scientists to store values of various Earth properties on a grid that spans the globe. GeoTess facilitates access to a multi-level triangular tessellation of a unit sphere, including find the index of the triangle in which an arbitrary position on the sphere resides and computing the interpolation coefficients that should be applied to data stored on the nodes of the tessellation that defines the triangle.
Database communication has been rewritten using new object-relational features available in Oracle 9i. New features in LocOO include a redesigned internal architecture implemented to enhance flexibility and to support simultaneous multiple event location. LocOO relies on PGL for all predicted quantities and is designed to fully exploit all the capabilities of PGL that are relevant to seismic event location. It uses a linearized least-squares inversion algorithm (the Geiger method), enhanced with Levenberg-Marquardt damping to improve performance in highly nonlinear regions of model space. The Location Object-Oriented (LocOO) tool computes seismic event locations and associated uncertainty based on travel time, azimuth, and slowness observations. New features include enhanced station object processing low-level conversion to a new core graphics visualization library, the visualization toolkit (VTK) additional visualization support for most of the PGL geometric objects and support for the Environmental Systems Research Institute (ESRI) shape files (which are used to enhance the geographical context during visualization). It is written as a graphical user interface (GUI) that can directly access objects stored in any PGL file database and display it in an easily interpreted textual or visual format. The Data Manager (DM) tool provides access to PG data for purposes of managing the organization of the generated PGL file database, or for perusing the data for visualization and informational purposes.
CONSTRUCTION OF TRIANGLE TESSELLATION WINDOWS
Recent improvements include conversion of the flat-file database (FDB) to an Oracle database representation automatic access of station/phase tagged models from the FDB during location modification of the core geometric data representations a new multimodel representation for combining separate seismic data models that partially overlap and a port of PGL to the Microsoft Windows platform.
CONSTRUCTION OF TRIANGLE TESSELLATION SOFTWARE
The library provides data representations and software models to support accurate and efficient seismic phase association and event location. The PGL represents the core software library used by all the GNEM R&E tools that read or write PGL data (e.g., KBCIT and LocOO). The Parametric Grid Library (PGL) provides the interface to access the data and models stored in a PGL file database. New features in KBCIT include a new variogram autofit algorithm the storage of database identifiers with a surface the ability to merge surfaces and improved surface-smoothing algorithms. KBCIT not only produces the surfaces but also records all steps in the analysis for later review and possible revision. It is used to analyze raw data and produce kriged correction surfaces that can be included in the Knowledge Base.
KBCIT is an interactive computer application to produce interpolated calibration-based information that can be used to improve monitoring performance by improving precision of model predictions and by providing proper characterizations of uncertainty. The primary PG population tool is more » the Knowledge Base calibration integration tool (KBCIT). In this presentation we discuss the latest versions of the complete suite of Knowledge Base PG tools developed by NNSA to create, access, manage, and view PG data. PG data can be used to improve signal detection, signal association, and event discrimination, but so far their greatest use has been for improving event location by providing ground-truth-based corrections to travel-time base models. One of the most important types of data in the National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Engineering (GNEM R&E) Knowledge Base (KB) is parametric grid (PG) data.
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