C. Approach and Capabilities
1.0 Graphical User Interface (GUI) Tools
Window-based graphical interfaces have become a common feature of most software systems. Most users expect an easy-to-use menu driven application. This is the idea behind a Graphical User Interface (GUI). To build a GUI, IDS uses the X window system and the OSF/Motif Widget Set. The OSF/Motif Widget Set is based on Xt Intrinsics, a set of functions and procedures to access the lower levels of the X Window System. These tools allow IDS programmers to assemble a GUI quickly and efficiently. The Motif Widget Set can be used with a number of window managers, including the Motif Window Manager.
GIS are used to manipulate, analyze, and develop spatial data. Spatial data are best described in the form of maps. Once data are stored spatially in a computer format, they can be used to model actual spatial systems.
WetScape uses version 4.1.5 of the Geographical Resources Analysis Support System (GRASS). GRASS is a public domain, image processing system and GIS developed and maintained by the Environmental Division of the US Army Construction Engineering Research Laboratories (USACERL) in Champaign, Illinois.
GRASS is primarily a raster-based GIS. The source code for GRASS is public domain and has a large and active user community that continues to develop improvements to the system. The GRASS system has been used extensively and has proved to be a very valuable tool for spatial modeling. A set of software libraries is provided with the GRASS, and can be incorporated directly into a GUI to preform spatial analysis.
WetScape is comprised of a series of separate, but interrelated data analysis modules that each contain a distinct set of tools designed to accomplish certain tasks. Each module has or will have an associated GUI within WetScape designed to facilitate use and to guide the user through the settings and functionality. The analysis modules link spatial information analysis features with data manipulation, modeling interface, and user defined selections. This modular organization was implemented to anticipate the need to expand capabilities in the future, while still allowing the base system to remain intact and functional.
WetScape modules are accessed through the main WetScape interface which also supports generic operations such as: 1) estimating the water budget associated with a given area based on consumptive use variables; 2) editing of individual cells within a raster map, and 3) viewing elevation maps, or GIS products for comparison with digital aerial photos images.
Analysis modules were developed to explore topographic features, to identify areas based on defined criteria, examine surface hydrology characteristics and projected wetland conditions, and to develop and analyze potential watershed management strategies. Identified analysis modules and their respective development status are Basin Wide Siting (BWS), Projected Wetland Analysis (PWA), Basin Wide Analysis (BWA). Additional modules were identified for future development including Local Site Evaluation (LSE), Case Study Analysis (CSA), Case Data Base (CDB), Water Quality Loading (WQL), and Hydrologic Loading (HYD).
3.1 User Interface Design
The WetScape Interface shown in Figure 1 contains areas for display and control of WetScape functions.
The main areas shown in Figure 1 are the following:
- Title Bar - indicates the Interface name and version number.
- Pull-down Menus - contain control items for selecting and displaying maps, for modifying the display of maps, and for producing output.
- Mouse Actions - control what action the mouse will perform when clicked.
- Main Display - is the area where maps and pop-up windows will be displayed.
- Message Display - shows status and control messages describing actions by the user and processes called by the Interface.
- File Name Display - shows the map location, mapset, type of raster map display, and also displays the file name of the user's workspace.
- Map Statistics - show the Universal Transverse Mercator (UTM) coordinates of the map area that is displayed.
The WetScape Interface is started from the command prompt by typing wetscape. This command invokes a shell script that sets system definable variables and controls the WetScape environment. The executable XWetscape is invoked and the proper GRASS directories and files are created. After the Interface starts, the following display will be shown.
WetScape uses data to develop management scenarios using multiple analysis modules and map management tools.
4.1 Project/Scenario/Workspace Concept
The goal of the project/scenario/workspace concept is to make it easy to find and store various analysis performed on a basin-wide scale. This concept builds on the GRASS structure of location and mapset. Each project/scenario/workspace is saved in the user's grass mapset (mapset names are usually the user's login) under a directory specified in the user's ~/.grassrc file. The user's mapset should have a directory called WetScape, in this directory is a directory is called projects. Projects are defined regions associated with a raster map. The raster map is stored in a mapset and associated with a location (See Figure 2).
A new raster map can be selected with the options in the Maps pull-down menu (See Section 4.2). Scenarios are groupings of workspaces in a particular project and workspaces are associated with individual analysis modules (See Figure 2).
- Project refers to an area in a raster map (such as an elevation map).
- Scenario refers to a management objective for a Project.
- Workspace refers to a tool used to achieve the management objective and the associated data for one scenario.
4.2 Map Tools
The GIS capabilities of WetScape includes tools to modify raster, vector, site, and label maps. Raster maps are the main computational component of the spatial capabilities, they are grid based maps with each cell formed by the grid having a unique value. The grid of a raster map defines the display resolution, for example a 30 meter map will have cells that are 30 x 30 meter areas in size. Vector maps define the boundaries of spatial features or linear features, site maps define point locations with associated data, and labels are text that can associated with spatial features. The maps in WetScape are organized based on the GRASS system of locations and mapsets. Locations are large physical regions, that contains mapsets with individual datasets for different users. For each study site, multiple maps may be available, and these maps are located in different mapsets or groups of maps. One of the most common mapsets is the PERMANENT mapset that contains final versions of each map. The user can also have their own mapset that has slightly different maps. The following tools have been developed for WetScape to use these maps:
- Displaying Raster Maps - Raster maps are grid-based maps that have data stored spatially by cells. Raster maps can be stored and used for modeling in WetScape. Elevation raster maps are used for many of the analysis modules which can then create aspect or other maps used for analysis.
- Displaying Vector Maps - Vector maps are line based maps that describe linear features such as streams or county boundaries. These maps can be overlaid on the raster maps and used to orient the user with local features.
- Displaying Site Maps - Data can be tied to site locations and displayed when the site is selected. For example climate stations can be populated that would have historical temperature data.
- Displaying Paint Labels - Paint labels are text labels that can be tied to a location and used for displaying the name of a town or other features.
- Displaying Map Histories - History of where and how the coverages were populated for Wetscape can be displayed.
- Stacking Raster Maps - Multiple raster maps can be displayed, by stacking them.
- Masking Raster Maps - The mask operation can be used to display and compute values for an irregular piece of a raster map.
- Copying Maps - This feature can be used to copy raster maps from one mapset to another.
- Removing Maps - This feature can be used to remove raster maps from a mapset.
4.3 Basin Wide Siting (BWS)
This analysis module is generally designed to be utilized for the initial review of landform characteristics that influence selection of specific sites or areas of interest. The BWS module provides tools to assist users in defining criteria to apply spatial analysis to raster map information. This is accomplished through a model development interface called the Spatial Analysis Model Interface (SAMI). The SAMI is used to create script programs comprised of a sequence of GRASS operations that are applied to accomplish specific functions.
Spatial models are being evaluated that could be used to identify regions that have geomorphic features associated with different wetland characteristics such as: 1) Riparian; 2) On-Channel; 3) Off-Channel; and 4) Depressional. Selected model templates are currently under development to provide the user with a set of functional terrain-based models for use in testing. The SAMI is flexible to accommodate different types of spatial information data or to combine GRASS operations with other UNIX programs to develop more sophisticated models or to create models with more complicated multiple evaluation criteria.
4.4 Projected Wetland Analysis (PWA)
The PWA tool is designed to allow the user to evaluate a selected site area in greater detail. It is an important WetScape utility because it allows the user to evaluate the actual physical topography of an area with respect to projections of local surface flooding conditions. The user places an artificial control line, either open or closed, to define the area to be examined (Figure 4). A set of vertical elevations can then be selected to evaluate the water area and volume corresponding to flood stage. Three elevation zones can be specified to show the areal extent associated with each depth. These features might be employed to examine stage volume characteristics, or evaluate how a created wetland might respond to differing water surface elevations.
The open control line is generally used to evaluate branched riverine watershed drainages or local catchments. The closed control line is utilized in areas with depressional features (e.g. prairie potholes area in central U.S.) or to isolate regions for evaluation of surface topography.
The results of the PWA analysis can be saved to a database according to the respective maps which can then be utilized for analyses at the watershed or basin-wide level. In this case, the attributes from individual site maps are combined to form a composite map. The composite map can then be utilized in the analysis of impacts of several wetlands throughout a basin.
The PWA module uses an elevation map to develop the storage characteristics of a projected wetland. The user can adjust these controls to examine and optimize up to three depth zones in the projected wetland site, representing emergent plants, floating plants, and open water or other user defined zones of interest. The zone depths are completely definable by the user. Total surface area, and volume of the flooded area is also displayed to the user in graphical and tabular forms.
4.5 Basin Wide Analysis (BWA)
The BWA analysis module consists of several models that develop totalizing reports for aggregating attributes assigned to the spatial data imported to the system or data generated by other analysis modules. For example, attributes associated with zone features defined in the PWA module could be compared for different hypothetical implementation strategies. In the most simple form, BWA supports totalizing spatial features according to area, volume, or linear attributes. BWA models can be designed to take advantage of the interactive environment of the WetScape interface to work with the other analysis tools, SAMI models or as preliminary stages for use of external resource models. Support for interface with other external hydrologic and water quality models would be undertaken in subsequent development stages.
4.6 Water Demand Module
This module can estimate the consumptive use of an area from evapotranspiration of the vegetation. A per unit area consumptive use coefficient can be entered for each category of a vegetation map and estimated for local areas over time, based on weather data. Note, the dataset for any area using WetScape must be populated to use this module.
WetScape was developed as an interactive workstation that combines different operations in a readily accessible environment to allow flexibility in user expertise and application. WetScape tools are presented in a user-friendly Graphical User Interface (GUI) comprised of windows, icons, and pull down menus designed to guide users through various analysis tools and simulation routines. At the core of WetScape are a Geographic Information System (GIS) and data management utilities. GIS analyses utilize the Geographic Resource Analysis Support System (GRASS) version 4.1.5 [USACERL, 1993]. The GUI currently operates under the SUN Microsystems UNIX-based operating system and X-Motif library. WetScape workstation capabilities were developed using the C programming language, TeleUSE by TeleSoft, Inc., and spatial analysis accommodated by the GRASS operations.
As an appraisal-level GIS for screening and visually assessing data, WetScape functions are designed to examine spatial geographic data, incorporate additional data, and to allow interaction with external hydrologic, water quality, and watershed models. Digital elevation map coverage is the foundation of the terrain-based analysis tools. WetScape utilizes digital raster map data; however, spatial data coverage can be imported in either digital raster form or as point and linear format data and then spatially interpolating within the GRASS system.
WetScape can accept data types ranging from simple site survey information to more intensive GIS data layers. Actual data limitations may depend on system capacity and acceptable user pre-processing effort. WetScape also incorporates specific information that is associated with spatial coverage and other data that is used for tracking user-defined projects and operations. The GIS operations are not constrained to specific data types, so the desired level of resolution can be adjusted according to application needs or practical limitations.
A convenient way to access spatial information is by directly incorporating Digital Elevation Model (DEM) or Digital Line Graph (DLG) data that can be purchased at nominal cost. For example, depending on the area of interest, DEM and DLG files available from the U.S. Geological Survey (USGS, 1994) and other sources. Commercial data coverage of relatively coarse resolution might be appropriate for initial assessments, then as information becomes available, it could be incorporated to develop more detailed analysis. This allows the user to begin with a minimal investment, and still have the option of refining investigations later. A similar approach might be applied to evaluate larger areas during early planning, and then to focus on promising areas identified during the initial review stages.
The WetScape Project team has worked together closely throughout the project and a version of WetScape is maintained at the IDS Group in Fort Collins and at the Technical Service Center in Denver. The software includes a HTML based copy of the user manual that can be accessed from the interface.
In order to conduct analysis with maps, tools and systems are required that provide the capability of map development, modification and reorganization, display, analysis, reporting and summarization. The data base, remote sensing and geographical information system technologies have been collected together to provide these capabilities. The capabilities of the GRASS GIS, public domain data base and the tools provided within the UNIX operating system offer the analysis basis. When these tools are insufficient or inefficient in providing a needed capability, custom programming has been undertaken to develop additional capabilities. The process has been proto-typed using UNIX shell scripting environment because of the convenience and embraceable nature of the interactive environment which facilitates rapid proto-typing.
Therefore, training was done with Reclamation personnel on the use of these tools for future management of the system.