- Software development, prototyping, testing and validation,
software tools, common data formats, networking, client-server architecture.
- DRAFT Release 0.1, 17 November 1996
- Author: Kurt Fedra
Data Exchange Formats
For the data exchange between the project participants, the following data
standards are recommended:
- Text files:
- plain ascii
- Word (*.doc files): uuencoded, as mail attachments, or by binary
- RTF files (ascii)
- Imagery and graphics:
- GIF files (please note that larger files should NOT be sent as mail
attachments, but transferred by ftp;
- TIFF (5.0, compressed) for 24-bit data
- GIS data:
- Arc/Info export format
- DLG (USGS Digital Line Graph format)
- DXF (least desirable)
- satellite imagery and raster data in any convenient format INCLUDING a
- Model Data:
- ascii data (with an appropriate format description, and where
appropriate with the necessary reading routines)
- binary data: together with description and the appropriate reading
Client-Server Data Exchange
Client-server data exchange is based on the http protocol.
The Demonstrator uses initially simple ascii files based on the protocol
specifications for model scenarios and model result transfer.
This uses a simple protocol of keyword:value pairs, for example:
StartTime:199710250000 # yyyymmddhhmm
TimeStep:1480 # in minutes
RunLength:96 # in time steps
NoxIndustry:1.2 # multipliers for data matrices
Meta-Data: The HDF Hierarchical Data Format
HDF is a library and platform independent data format for the storage and
exchange of scientific data. It includes Fortran and C calling interfaces,
and utilities for analyzing and converting HDF data files.
HDF is developed and supported by NCSA, and is available in the
public domain. HDF is used world-wide in many fields, including
Environmental Science, Neutron Scattering, Non-Destructive Testing,
and Aerospace, to name a few.
Scientific projects that use HDF include NASA's Mission to Planet
Earth, and the DOE's Accelerated Strategic Computing Initiative.
A detailed description of HDF is available from the
NCSA's web server .
The primary intended application of HDF in ECOSIM is for the storage and
Internet publishing of model scenarios
The main relevant features are:
HDF stands for Hierarchical Data Format. It is a multi-object file format
for the transfer of graphical and numerical data between machines.
HDF is a versatile file format. It supports six different data models.
Each data model defines a specific
type of data and provides a convenient interface for reading, writing,
and organizing a unique set of data elements.
HDF is a self-describing format, allowing an application to interpret
the structure and contents of a file without any outside information.
HDF is a flexible file format. With HDF, you can group sets of related
objects together and then access them as a group or as individual objects.
There are pre-defined sets for raster images and
floating point multidimensional arrays. Users can also create their own
grouping structures using an HDF feature called vgroups.
HDF is an extensible file format. It can easily accommodate new data
models, regardless of whether they are added by the HDF development team
or by HDF users.
HDF is a portable file format. HDF files can be shared across
platforms. An HDF file created on one computer, say a Cray supercomputer,
can be read on another system, say IBM PC, without modification.
HDF is available in the public domain.