This paper describes the application of aerial photography and GIS technology to develop flexible and transferable methods for multi-spatial scale characterization and analysis of riparian corridors. Relationships between structural attributes of riparian corridors and indicators of stream ecological conditions are not well established. As part of a research project focused on assessing riparian-stream systems in agricultural landscapes of Oregon's Willamette Valley, GIS land cover/land use databases were created from 1997 aerial photography and digital orthophotography for 23 predominantly agricultural watersheds, including detailed land cover-land use coverages within 150 m of perennial and intermittent streams. GIS functions were used to partition the stream networks at various lateral-longitudinal scales to quantify land cover/land use and to generate functionally relevant metrics of riparian vegetation, such as its composition, width, and continuity. The methods developed provide considerable flexibility for generating metrics characterizing attributes of riparian corridors and for exploring relationships among these metrics and indicators of stream ecological condition.