1. Introduction
[XMDF Documentation]

Multi-dimensional numerical modeling studies have traditionally necessitated a large number of big data files (both input and output). The shear number of data files can lead to confusion, misplaced or lost data, and poor communication. In addition, each numerical model uses and generates data files in its own format making the sharing of data and coupling of models difficult. Add to this the fact that files typically need to be ASCII (inefficient) in order to be passed across platforms, and the result is that too much computer time, computer space and human interaction is needed in the modeling process.

To address these problems, the ERDC has taken the initiative to develop a standard file format to be used in modeling studies. In the first phase of this project, the Environmental Modeling Research Laboratory (ERML) at Brigham Young University has developed a standard format for geometry data storage. In this context, geometric data includes:

• river cross-sections

• 2D/3D structured grids

• 2D/3D unstructured meshes (including sets of scattered data points triangulated into a TIN)

• geometric paths through space with associated time data

The data file will be able to store multiple instances of each of these data objects along with data sets associated with the object. Data sets represent scalar and vector arrays such as model solution data. In addition to developing the standard format, the EMRL has provided an application programming interface (API) that developers of numerical codes can use to quickly and easily access this format without minimal difficulty. This standard available to all of ERDC and everyone is encouraged to adopt it.

The following section gives background, motivation and an overview of the approach being used. The third section includes technical implementation details for programmers.