Marine Geoscience Data System

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GeoMapApp

About GeoMapApp©

Created by William Haxby, with support from LDEO and the National Science Foundation

GeoMapApp© (formerly MapApp) is a freely downloadable Java™ application, which permits users to browse bathymetry data from the world’s oceans, generate and download custom grids and maps, and explore a variety of other data types. The default basemap is the Global Multi-Resolutional Topography Synthesis. The GMRT is dynamically maintained and is composed of grid and image tiles, at a variety of grid node spacings, that are accessed via the Internet by GeoMapApp© to dynamically compose seamless grids and images for analysis and viewing. Bathymetry may be viewed to resolutions as high as 50 meters, where high-resolution data exist. As new data are added to the compilation, they are immediately visible to users worldwide without the need to download a new version of GeoMapApp©.

Bathymetric data can be viewed in a Southern Hemisphere Polar Stereographic or Mercator projection. In the Mercator view, the Smith and Sandwell (1997) predicted topography compilation is used as a regional background map. For the Polar projection, south of 60°S, we use the BEDMAP under ice seabed topography compilation from the British Antarctic Survey (Lythe et al., 2000). These regional background maps can be dimmed to display the areas of higher-resolution multibeam bathymetry data coverage. The user can zoom and focus on color shaded relief images, customize the map display and download their custom map images as a PostScript or JPEG file. Grids can be loaded at the viewing resolution, and data can be contoured at a user-specified interval. Grids corresponding to the user-defined map view can be downloaded as ASCII lat-long-depth files or as GMT compatible NetCDF grid files both with (unmasked) and without (masked) the background regional bathymetry compilation. Multibeam ping files can be downloaded for users wishing to create their own grids or to further manipulate the raw data files. Capabilities are also provided for digitizing and downloading points and bathymetric profiles extracted from the gridded data.

In addition to bathymetry data, the map browser also provides access to ship-acquired trackline geophysical data with the ability to select a trackline of interest and view corresponding profiles of gravity, magnetics, or topography. GeoMapApp© links to the PetDB (Lehnert et al., 2000) petrology database and enables a user to view, select, and download geochemical data from an area of interest along the world’s mid-ocean ridges. Isochrons from Muller et al. (1997) can be superimposed on the bathymetry, showing seafloor age. Earthquake locations from the International Seismological Center can be plotted. The browser also provides access to the ocean seismicity data set of the NOAA, Pacific Marine Environmental Laboratory. This data set includes seismicity detected with moored hydrophone arrays from the northern and equatorial Mid-Atlantic Ridge and East Pacific Rise, and the Navy-operated SOSUS array in the Northeast Pacific (e.g. Fox et al., 1995; Dziak et al., 1995). Users can create animations of seismic events, which can then be saved as QuickTime movies.

Single-channel seismic profiles from the LDEO archives can be viewed providing information on sediment thickness and stratigraphic relationships between sedimentary layers and igneous basement. These data were scanned from photographic negatives by the National Geophysical Data Center (NOAA) and have been geo-referenced and incorporated into the map browser. The data were routinely collected during expeditions of Lamont ships in the 1960’s and 1970’s and provide a valuable resource, which until the NOAA data rescue effort, were only available in analog form. Capabilities are provided to digitize seismic horizons, and download digitized files as well as seismic images. A viewer with similar capabilities for multi-channel seismic (MCS) data provides access to high-resolution MCS profiles from the many locations worldwide. GeoMapApp provides access to all of these data types, and many more, which allows the user to explore diverse data sets and generate custom maps from a single interface.

GeoMapApp© is under active development. New high-resolution bathymetry data are periodically added to the database, new functions are added to existing database interfaces, and new databases are being developed. Data sets that have become accessible through GeoMapApp© include ODP (Ocean Drilling Program) data products (including the Borehole Research Group's well-logging database), ocean bottom photographs, oceanic heat flow, and the LDEO Core Repository's sediment core database.

GeoMapApp© is downloaded to a user's machine and is run with a live Internet connection that permits periodic connects to our server as new data are requested. The application runs on a wide range of modern operating systems (MacOS 10.4 and above, Windows 98, 2000, XP, Vista, Solaris 2.7 and up, and GNU/Linux 2.4 and up). Support for the development of GeoMapApp has been provided by Lamont-Doherty Earth Observatory and the National Science Foundation.