SECTION 4: SEAGRASS MAPPING AND LANDSCAPE ANALYSIS MONITORING DESIGN I. Mapping to Determine Seagrass Status and Trends The current standard methods for determination of seagrass status and trends

The current standard methods for determination of seagrass status and trends involve mapping from 1:24,000 scale true color, not color infrared, aerial photography (NOAA-CSC 2001). Analysis of this scale color photography for seagrass distribution has traditionally been performed by photointerpretation of 9” x 9” positive phototransparencies, followed by digitization of seagrass polygons from map overlays and compilation of digital data into a spatial database (i.e. normally GIS). Details of these seagrass photointerpretation and computer mapping methods are thoroughly described in Dobson et al. (1996), Pulich et al. (1997) and most recently by NOAA-CSC (2001). For seagrass mapping projects using aerial photography of all scales, these techniques would generally be utilized, although some technological modifications have greatly streamlined the delineation and digitization steps (e.g. optical transfer georegistration instrumentation, and digital scanners are now available). Rigorous standards and specifications apply in all phases of the work; and all required procedures must be followed to ensure accuracy and quality of status and trends seagrass data derived from the aerial photography.