MAPS

        In addition to the figures viewable directly from the text, the CD-ROM contains a directory called maps.  This directory contains files in Arc/INFO format and consists of the complete sidescan sonar mosaic, bathymetric data, ship tracklines, Puerto Rico coastline, and sediment sample locations and analysis information.  All of the data are mapped in a Universal Transverse Mercator projection (UTM), zone 19, using the WGS84 reference ellipsoid.

There are 8 directories under the directory maps which contain Arc/INFO coverages and grids.  These directories are:

BATHY
        The digitized bathymetry was furnished courtesy of the Puerto Rico Water Resources Division.  In this Arc/Info line coverage, the bathy-id attribute corresponds to the bathymetric value in meters.

BIOSAMPS
        This Arc/INFO point coverage shows the locations of sediment samples collected for biologic analysis.

COAST
        The Puerto Rico coastline was digitized at 1:100,000 from the following NOS charts - #25641, 25677, 25671, and 25668.

INTERP
        This Arc/INFO polygon coverage represents the general geologic interpretation of the sidescan-sonar imagery.

SAMPLES
        The sediment samples were collected using a Shipek grab sampler.  The sediment textural analysis results are included in this Arc/INFO point coverage.

TRACKS
        The tracklines were derived from the sidescan-sonar navigation at 1 minute intervals.  The tracks-id of this line coverage corresponds to the trackline number assigned during data collection.   Included in this directory is a file called allnav.txt which contains the 1-minute sidescan-sonar navigation.  This file has 3 columns of information: Julian day and time (in GMT); latitude; and longitude.  The beginning of each trackline is indicated with the line number.

RAWGRD
        This directory contains the grid of the sidescan-sonar imagery that has not undergone any image enhancement.   This grid was generated using the Arc/INFO gridimage command.  The resolution of the grid is 1m/pixel.

SONARGRD
        This directory contains the grid of the sidescan-sonar imagery that has had an image-enhancing stretch applied to the pixel values.   This grid was generated in the same way as rawgrd.  The resolution of the grid is 1m/pixel.

SIDESCAN
        This directory contains 2 'TIFF' images and their associated world file for use in Arc/Info.  The file 'rawsonar.tif' is the sidescan-sonar mosaic with no image enhancement applied.  This file is the image file used to generate rawgrd.  The other 'TIF' image, 'anasco.tif', is the enhanced image from which sonargrd is derived.   These 'TFW' files associated with each of these images allows Arc/INFO to geographically register the images.  The resolution of these images is 1m/pixel.