USDA ARS

Software Tools for Hydro-Climatic Modeling and Analysis


Introduction to the Image Processing Workbench (IPW)
ARS - USGS Version 2


D. Marks, J. Domingo, and J. Frew

The Image Processing Workbench (IPW) was initially developed at the University of California, Santa Barbara, by James Frew (Frew, 1990) to provide a suite of software tools for analysis and processing of remote sensing data. At the time, the term "image processing" was not synonymous with image display, mapping, and many of the other features commonly built into GIS and mapping systems (for example see: USACE, 1988, ESRI, 1990, Precision Visuals, Inc., 1994). IPW was instead designed to provide a robust set of software tools to facilitate the development and testing of algorithms that are applied explicitly to raster image data.

The IPW system is tightly coupled to the Unix operating system and the C programming language. It provides scientists, engineers, and programmers a flexible and robust toolkit for algorithm and application development to support hydro-climatic modeling and analysis.

The predecessor to IPW was the QDIPS system, also developed at UCSB by James Frew and Jeff Dozier (Frew and Dozier, 1984). The QDIPS system was extensively modified by Danny Marks, and others, to begin to extend these software tools to applications in hydrologic and bio-physical modeling in addition to image analysis and remote sensing data processing (for example, see: Davis, 1986, Haston, 1986, Marks, et al., 1986, Marks, 1988, Marks, et al., 1988, McGurk, et al., 1989, Marks, et al., 1992).

In the early 1990's, a group at the EPA Environmental Research Laboratory in Corvallis, OR, under the direction of Danny Marks, began to integrate the hydro-climatic utilities developed under QDIPS into the IPW system. The modified system, first made publicly available in 1991 (Longley and Marks, 1991) and then updated in 1992 (Longley, et al., 1992), provided the first extensive software toolkit to support spatial hydrologic modeling and analysis (for example, see: Dolph, 1990, Marks, 1990, Dolph and Marks, 1992, Dolph, et al., 1992, Marks and Dozier, 1992, Phillips, et al., 1992, Marks, et al., 1993, Kimball, 1994, Neilson and Marks, 1994, Phillips and Marks, 1996, Turner and Marks, 1996, Dodson and Marks, 1997).

During much of this period, however, QDIPS was still in use for point processing.The modified IPW system was restricted to image applications. In 1996 the USGS group at the EPA facility in Corvallis, OR, began to integrate the point processing utilities from the QDIPS system into a re-designed IPW system.

This document describes the re-designed version of IPW, referred to as IPW, ARS - USGS Version 2. While Version 2 adheres to the original design criteria and includes nearly all of the original commands and libraries presented by Frew (1990) (see IPW Design Objectives), significant structural and functional changes have been made.

Functional Changes in Version 2

Structural Changes in Version 2


IPW documentation / Last revised 20 May 2009 / IPW web site