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<br />.f! ~ 2 \l 0 0 <br /> <br />Pre-process Component <br /> <br />Pre-process component functions include all data preparation and analysis functions needed to <br />meet the data and selecied parameterization requirements of a user-selected model. A goal in the <br />development of the pre-process component is to take advantage of the wide variety of existing <br />data-preparation and analysis tools and to provide the ability to add new tools as they become <br />available. Spatial data analysis is accomplished using GIS tools that the users have installed on <br />their computer system. Such analyses could include segmentation and characterization of a <br />watershed into subareas for distributed-parameter modeling. Digital elevation model (OEM) data <br />and selected digital data bases that include information on soils, vegetation, geology, and other <br />pertinent physical features would provide the data on which to develop such characterizations. <br /> <br />TIme-series data from existing data bases as well as from field instrumentation are <br />prepared for use in selected model applications by generating and combining these data into a <br />. single flat ascii file. Additional tools are being developed to detect bad or missing values, replaCe <br />bad or missing data via selected statistical procedures. aggregate data to longer time steps, <br />disaggregate data to shorter time steps, and apply transform functions to produce a new time- <br />series. Methods to create simulated time series from model output or from the analysis and <br />extrapolation of measured data to unmeasured points or gridded fields are also being developed. <br /> <br />The data base(s) used to~tore the spatial and time series data provide(s) the interface <br />. between the pre-process and model components. The goal is to enable the use of a variety of data <br />bases, dependent on user preference or prescribed needs. Interface to the model component can be <br />provided by the use of System Query Language (SQL) commands or filter programs that access <br />the data base. <br /> <br />.' <br /> <br />Model Component <br /> <br />The model component is the core of the system and includes the tools to selectively link process <br />modules from the module library to build a model and to interact with this model to perform a <br />variety of simulation and analysis tasks. These interactions are provided using a variety of X- <br />window and graphical techniques. The model component is discussed in more detail in a later <br />section titled Modular Model Concepts and Capabilities. <br /> <br />Post-process Component <br /> <br />The tools to analyze model results are included in the post-processing component. These include <br />a variety of statistical and graphical tools as well as the ability to interface with user-developed <br />special purpose tools. Statistical and graphical analysis procedures provide a common basis for <br />comparing module performance and can be used to aid in making decisions regarding the most <br />appropriate modeling approach for a given set' of study objectives, data constraints, and temporal <br />and spatial scales: ~ 91~ interface provides the v{sualization and analysis tools to display <br />spatially distributed model results and to analyze results within and among different simulation <br />runs. <br /> <br />3 <br />