The Comprehensive Environmental Assessment System (CEAS) is the ArcInfo-based Geographic Information System (GIS) application that resulted from a two-year software integration effort of the Naval Oceanographic Office (NAVOCEANO). Its goal was to provide an integrated set of tools for oceanographic, acoustic, geophysical, geopotential, and bathymetric data assessment and product generation for NAVOCEANO users and their customers. The initial phase has been completed. Refinements and new capabilities development are ongoing.

The CEAS working environment utilizes the ArcTools approach, but also integrates Geographic Resource Analysis Support System (GRASS) GIS, Oracle, PV-Wave and custom FORTRAN and C routines. This application utilizes the environmental data holdings of NAVOCEANO (i.e. the Integrated Data Base Management System) and other Government activities. Standard GIS functions are provided, with robust data import/export functions and customized utilities. Integrated applications include range-dependent acoustic modeling support, deployment planning, survey design, oceanographic profile editing, global ocean current climatology and time series data products. Unique functions include filled cross sectional graphs of sediment layers, great circle and terrain-following distance measurements, cable payout parameter calculations, multibeam swath coverage calculations, transmission loss rosette displays, multi-run acoustic model set ups, three-dimensional (3D) and animated visualization displays, grid based modeling, and spatial and temporal data base queries.

This paper describes an ArcInfo application that supports Navy environmental data requirements. Discussions include background of how and why the system was developed, general and specific system functionality, and special features of interest to the Environmental Systems Research Institute (Esri) community.

NAVOCEANO provides meteorological, oceanographic, and mapping, charting and geodesy (MC&G) support to the Fleet as part of the Commander, Naval Meteorology and Oceanography Command (COMNAVMETOCCOM). NAVOCEANO conducts multi-sensor ocean surveys, participates in scientific and technical programs, and manages Navy standard environmental data bases. This effort supports Department of Defense (DoD) meteorological and oceanographic (METOC) environmental requirements for effective weapon/sensor system performance.

The CEAS addresses the continuing Fleet requirements for multi-disciplinary environmental data assessment and analysis, survey and special deployments planning, and Anti-submarine Warfare (ASW) Advanced Systems support. Current war-fighting direction has undergone a fundamental shift from open-ocean warfare to expeditionary warfare in critical littoral and sublittoral regions. In response, the CEAS was adapted to support flexible and interactive spatial data access, display, analysis, and hard-copy generation tools that use standard NAVOCEANO data.

NAVOCEANO is responsible for the collection, processing, tailored product generation, and maintenance of global-scale oceanographic data holdings. These data are used to generate products in support of the Navy's tactical and strategic operations. In addition, NAVOCEANO has numerous working agreements with other U.S. and foreign Government activities and research institutions for data sharing. Huge volumes of data are collected via ships, satellites, and aircraft, and are processed at NAVOCEANO by technical experts within the appropriate Information Systems (IS).

A comprehensive list of data types can be utilized within CEAS, including bathymetry (ocean bottom topography); acoustic bottom backscatter imagery; wrecks and obstructions; gravity; water column temperature, salinity, and sound speed; currents; sediment samples; sediment type and characteristics; and sub-bottom morphology. Other data types derived "on- the-fly" include bottom roughness, slope, and aspect (from bathymetry); omnidirectional ambient noise (from components); as well as 3D bathymetry grids for use in "fly-throughs" performed in the GRASS environment.

A central part of NAVOCEANO's mission is to provide accurate and timely characterizations of the ocean's physical environment for acoustic performance prediction analyses and models. CEAS was designed to interface with NAVOCEANO's Integrated Data Base Management System (IDBMS), the product of a recent modernization effort, to improve data access and management, using state-of-the-art technology. IDBMS is a logically centralized but physically distributed warehouse of scientific data that use the Oracle relational data base management system in a multilevel design. All of NAVOCEANO's mission-critical configuration-managed data holdings are accessible to authorized users through IDBMS. This "core data" includes processed, ready-for-product-use and configuration-managed data sets. The IDBMS core data bases are distributed throughout the technical ISs in a client-server mode, linked via a high-speed fiber-optic gateway. A relational catalog of "metadata" and supporting tables includes source, inputs, survey information, and accuracies for core data in relational and native format. High-volume data, such as images, remain in native format with relational "pointers" in the catalog.

Currently, the CEAS interface queries IDBMS based on the Minimum Bounded Rectangle (MBR) defined for specific data holdings, performs Structured Query Language (SQL) queries and extracts data in ASCII format. Appropriate coverages are automatically created within CEAS, along with any derived coverages as described above.

Supported data types within CEAS are point (salinity, temperature, sound-speed profiles, and grab samples); line (contours, and shoreline); polygon (geology, anomalies, geophysical properties); grid (bathymetry and derivative types); image (acoustic backscatter); TIFF images (photographs); and associated attribute data. The CEAS interfaces are shown in Figure 1.

Figure 1.

In most cases, CEAS assumes that input data have been properly processed and quality assured prior to project ingest. Processing is performed by the owning IS, using various tools developed specifically for each data type. In-house-developed tools include "SwathEdit", for the editing of swath bathymetric data; "Chrtr", a minimum curvature spline algorithm for the creation of 2D gridded fields including bathymetry, gravity and geoid data; and "Iscrblr"; used for interactive grid editing. Acoustic backscatter imagery is processed using the Unified Sonar Image Processing System (UNISIPS, Ref 1.), including image processing and digital mosaicing (georeferencing) of the acoustic backscatter imagery. Temperature, salinity and sound-speed data sets are accessed and manipulated spatially and temporally using the NAVOCEANO Interactive Data Analysis System (NIDAS, Ref 2.). Use of standard Navy data bases and models, such as those contained in the Oceanographic and Atmospheric Master Library (OAML), also guarantees a high-degree of quality assurance for product generation.

Two categories of application requirements drove the original CEAS development: (1) optimal site selection for sea floor cable lay-downs; and (2) set up, display, and evaluation of passive range-dependent acoustic model data. From these core requirements, system functionality grew to include additional related and new functions. Currently the CEAS also provides:

• the ability to display, query, and analyze any CEAS data type;
• tools to support bathymetric survey track and core sample/ocean station site design;
• tools to support special CEAS data assessments and products; and
• tools for generic GIS data exchange.

These functions are integrated into a single program environment with a unified human-computer interface. A design goal was a common GIS working environment that was easily extensible to new data types, applications and platforms.

Figure 2 shows a typical CEAS project working screen. The flexible GUI imposes few constraints on user operations, while also supporting programming maintenance and upgrades.

The CEAS interface is project oriented and event driven, with an emphasis on interactive and iterative session activities. The main menu is ordered such that project operations generally flow from left to right, following the natural progression from project creation, to data loading, to general data display and query, to specific applications. Standard GIS tools are available at any level, and tailored tools are provided appropriately. To the extent possible, functionally similar GUI components are grouped together as follows:

• Project Definition and Data Definition are largely non-graphical with an orientation to form and list inputs.
• Display/Query/Analysis involves graphical map and x-y chart setup and display, utilizing the ArcTools View construct, well as form and list inputs.
• Tool bar functions are linked to the active view coverage to allow customized response. For example, the "Identify" tool variously shows latitude, longitude, and value, or custom text reports, images, table data, or profile cross sections.
• Applications are independently accessed from a second pull-down menu. Each application exhibits unique interface and control flow behavior tailored to its own requirements.
• Modeling Support requires a large amount of forms data entry and list selection for script execution. This submodule also requires custom graphical and query selections.
• Deployment Planning and Survey Design are largely line coverage display and editing, with the addition of swath and engineering data calculation and management. This submodule also requires form and list input.
• Oceanography requires graphical and keyboard selection and editing for map and x-y graph displays.
• Currents requires graphical and form selections. This submodule also includes Oracle data base query operations, which are form and list based.

Figure 2.

This section highlights some CEAS features of special interest to the ArcInfo community.

Data Definition. CEAS is built upon an INFO data base structure which manages tables of users, projects, data layers, views and associated details. Once project area boundaries are defined, desired data are retrieved and loaded from external formats (native or Oracle tables) into ArcInfo coverages as necessary. New data are routinely imported into a project, and the results of CEAS analysis are exported to other formats. The data definition module is the vehicle through which project data are managed.

Written in Arc Macro Language (AML) with C, FORTRAN, SQL, AWK code, and UNIX scripts, the data definition module maintains a tabular data dictionary. It is important to note that external ArcInfo coverages cannot be accessed by CEAS until imported into a CEAS project through this module. This design feature supports the referential integrity of the CEAS data base design.

The top-level menu displays a scrolling list of generic data categories. This construction provides a convenient method of sorting through large sets of data files. A second scrolling list displays project-specific data layers associated with the selected category. The user may browse the attributes of a selected data layer, import data from predefined formats to build new layers, export data into various formats, and delete data layers.

The data import option is the heart of the data definition function, providing the user with a mechanism within CEAS for bringing external digital data into user projects. Currently, nine formats are supported for converting map and attribute data into user defined ArcInfo formats. External formats include:

• GRASS (raster, vector, site and attribute data)
• imagery
• IDBMS (see Data Sources section for explanation)
• Chrtr (NAVOCEANO bathymetric data format)
• MFF (Master File Format for NIDAS data; see Data Sources section for explanation)
• ARC coverage (point, line, poly)
• ARC grid
• ARC generate (point, line, poly)
• ARC ASCIIgrid

The selection of a given format generates successively specific menus for additional data entry and subsequent processing, resulting in a project-specific, user-categorized ArcInfo data layer available for further analysis.

Another important element of the data definition module is the data export option, which allows automated conversion of ARC data layers to ArcInfo export files, ASCII files or GRASS data file formats. The user specifies the path and filename for the selected output format.

Display/Query/Analysis. Based on the MapTools View construct, the Display/Query/Analysis module allows the user to view, query and analyze coverages; to build composite coverages and views of data coverages available to and selected for the user's active project; and to generate and save procedures for use with other projects with similar requirements. A project must be active before work can continue in this module. The user must be the owner of the active project to save any composite coverages generated.

Deployment Planning. The deployment planning application includes the ability to plan the most efficient position to lay down a cable for performance and survivability. CEAS allows the analysis of bottom parameters, such as bathymetry, slope, roughness, and bottom backscatter, in an integrated environment. Here is where the power of a GIS is used. In many cases the most important parameters are bottom slope and roughness. By thresholding slope and roughness a derivative layer is created designating the optimal areas for a lay down. If these parameters are consolidated into one layer, other layers, such as bottom backscatter imagery, can be analyzed for the optimal areas. In addition, vector contours can be overlaid on the bottom backscatter imagery. Since bottom backscatter is both a function of grazing angle (terrain) and bottom type, draping bottom contours over the backscatter imagery allows the analyst to visually separate features in the imagery caused by topography from those caused by a difference in sediment type. This is shown in Figure 3. The route can then be digitized over these layers. Once the final route is digitized, pertinent engineering parameters can then be calculated and displayed in both tabular and graphical form. The 3D representation is helpful in this application for analyses using the SG3d module of GRASS, executed within the CEAS interface (for the Silicon Graphics version). The engineer has the ability to "fly" over the proposed cable route as a "sanity" check. Figure 4 depicts the cable over the terrain.

Figure 3. Figure 4.

Survey Design. This application primarily supports bathymetric survey planning. Proposed survey track lines can be created or imported, displayed, modified, and exported or deleted. In addition, bathymetric swath widths can be estimated for the track lines based on existing depth and equipment information. These data aid survey planners in optimizing data coverage for proposed survey operations.

A recent enhancement allows a more thorough survey planning capability. A user specified MBR can be filled with straight-line track segments at any line spacing and heading. Swaths can then be generated using best available bathymetry to estimate the resulting data coverage. Track segments are added, edited, or deleted as needed to optimize data coverage for the planned survey. Algorithms also exist for calculating ship time required for the survey plan.

Oceanography. The oceanography application utilizes temperature, salinity, sound-speed and ocean currents data types, represented as point coverages. CEAS spatially selects profile locations and plots vertical temperature, salinity or sound-speed profiles at those locations. Profiles may be edited and new profiles created. Afterwards, the edited profile may be written back to the data base and/or exported for other uses.

Fulfillment of CEAS requirements to edit and digitize profiles were inhibited by ArcInfo graphing tools, which proved inadequate for the desired formats and functions. An X11/Motif application was developed for use both within CEAS and as a stand-alone application. Similarly, INFO was not adequate for required data base functions, so Oracle tables were created. Once profiles are spatially selected, data base query parameters are specified within CEAS using modified ArcTools. Query results are written to a flat file, which provides input to the X11/Motif application. Afterwards, the edited profile may be written back to the data base and/or exported for other uses.

Profile data sources presently include the Master Oceanographic Observation Data Set (MOODS), the Generalized Digital Environmental Model (GDEM), and user-entered profiles. Profiles are first selected using CEAS tools, then passed to the "Profile Editor" application. The Profile Editor allows finer sub-sampling of profiles that were passed to it for individual work, and yet a backdrop of other profiles may be preserved for reference. Reference-only profiles include MOODS and GDEM data sets. The user-defined Aux1 and Aux2 profile data types are "editable". "Editable" profile depth/value pairs can be displayed and manipulated in graphical and tabular form. The X11/Motif Profile Editor application is shown in Figure 5.

Figure 5.

Currents Climatology. The Currents application is a climatology-based prototype that accesses statistical and time series Global Ocean Current (GOC) data bases in selected geographic areas of interest. Due to the profile-oriented nature of this application, some similarities with the Oceanography application may be noted. Data are represented by ARC point coverages, with each point representing data collected at multiple pre-set depths over time. Spatial selections are performed on the point coverages, but the actual data of interest are stored as data base attributes linked to the point coverage.

The complex problems associated with the storage and retrieval of time-series data in GIS, coupled with the large data holdings, presented difficult data-access problems. A relational data base was designed to store both monthly statistics and time-series data in Oracle, linking the data base records to the coverage features through unique identifying numbers. Each GOC point represents two kinds of information; a data base of daily data collections over time for each of seven depth levels from the ocean surface to the sea floor, as well as a data base of monthly averaged statistics containing summary information for the daily data sets. Information content includes:

• prevailing current speed and direction
• mean current speed and direction
• maximum current speed and direction
• standard deviation of current speed and direction
• other measures of variability

The ArcTools spatial selection and logical query tools were modified to accomodate the singular requirements of this data set. A SQL query builder was designed and implemented using SQL code and AML menus to bypass INFO, allowing direct relates to the Oracle tables. The ITEMLIST displayed in the query menu is created on-the-fly once a relate is established, allowing the use of appropriate attributes in building queries. External ASCII files are created to index data, to store query text and to formulate resultant data for product generation. Temporary Oracle tables are built to store query results prior to updating the ARC point coverage for display.

Several specific products are generated as a result of GOC data analysis, including statistical data histograms, wave vector calculations and display, and animated display of both time series and statistical data. These products utilize PVWave, which is accessed transparently through the application menu.

Tools & Utilities. The Tools & Utilities module offers the user fundamental GIS functionality and specific utilities which may be helpful in any module of CEAS. Such utilities include: calculating linear or terrain distances along a specified track; displaying a cross section view of bathymetry and sediment layers along a specified track; generating hard- copy output of the display; setting preferential units for measurable parameters used in CEAS (i.e., depth, temperature, range, sound-speed); querying specific locations on the display for coverage values; customizing a display for output.

The Tools & Utilities button on the main CEAS menu is a toggle switch which may be activated from any CEAS screen. When depressed, a Tools & Utilities bar menu is displayed at the lower left of the main display screen. This menu can be kept on the screen at all times, moved around for convenience, and turned off at any time.

The Tools & Utilities menu bar is divided into three main sections, including the standard ArcTool set and custom buttons tailored for CEAS applications. These custom utilities include:

• Measure Map
• Query Map
• Modify Attributes
• System Preferences
• Cross Section
• Bathymetry Profile (i.e., cable route)
• Customize Display
• Hard-copy Output
• Identify Tool

The Identify Tool's behavior depends on the feature class of the highlighted theme. Floating point grids yield a one-line location and value in the CEAS Information Window. Selection of a line coverage highlights the line in white and a pop-up window with the Arc Attribute Table (AAT) is presented. A point coverage feature changes color to white and the Point Attribute Table (PAT) is shown in a pop-up window. Selection of a polygon coverage causes the boundary to be highlighted in white and the Polygon Attribute Table (PAT) to be displayed in a pop-up window.

The ArcInfo environment proved to be an effective framework for the complex and ambitious CEAS project. The integration of standard GIS and custom functions, fusion of disparate data types and sources, and dynamic display, analysis, and product requirements of this project were challenging but not insurmountable. The resulting product has proven to be a viable component of several programs and new initiatives within NAVOCEANO, and CEAS has adapted well in a rapidly changing landscape of Naval support requirements.

1.) Lingsch, S. C. and C. Robinson. 1995. Processing, Presentation, and Data Basing of Acoustic Imagery, Oceans '95 MTS/IEEE Conference Proceedings, pp. 1582 - 1591.

2.) Software Design Document for the Naval Interactive Data Analysis System (NIDAS) Version 1.0, MSU/CAST, Stennis Space Center, MS, 39529-6000.