AbstractLegacy Data: Bringing It Into the 21st CenturyTrack: Imagery Author The California Department of Water Resources has amassed a vast array of map sheets and aerial photos. Some map sheets pre date 1900. The Department also has an extensive collection of aerial photos flown in 1938 and 1958. DWR has undertaken a program to scan the maps and photos, and create georeferenced images. Map sheets (scanned at 300 dpi) and aerial photos (scanned at 1000 dpi) are generally georeferenced to a minimum of 11 matching points. Sheets are converted to Esri grid format, mosaiced with adjoining sheets, and reconverted to TIFF files. A similar process is used for the photos. The imagery is especially useful for analyzing geomorphic changes along California's major river system. Also, the imagery aids staff in planning environmental restoration projects. Project completed thus far include 1923 Sacramento River maps and 1958 aerial photo mosaics of the Sacramento Valley. Completed projects are available at Cal Atlas (http://atlas.ca.gov/) Jonathan Mulder California Department of Water Resources 2440 main Street Red Bluff, California 96080 United States Phone: 530-528-7423 E-mail: mulder@water.ca.gov |