Methods

The preliminary shoreline type map was devised from (1) visual observations and oblique aerial photographs taken during low-altitude (less than 300 m above ground level) flights, (2) ground- and boat-based shoreline visits, and (3) analyses of radar and Landsat remote sensing imagery. During 1998, we conducted six low-altitude flights over the Delta (fig. 6a). The entire shoreline on the outer coast was observed at least once during these flights, and hundreds of photographs were taken. Kinematic GPS positions recorded during the flights allow precise positioning of the photographs. Much of the shoreline within the coastal bays was also photographed. In addition, we made ground and boat excursions to shorelines on the northwest portion of the Delta west of Punta Pescadores (fig. 39). While devising the preliminary classification scheme and map, we determined the type of coastal data, described above, required to complete the classification.