Ground surveys of beach profiles are conducted at select locations along the bay and Gulf shorelines. For convenience, temporary markers are installed or existing features are used as datum points and surveyed using geodetic GPS. An electronic total station is used to measure the profile along a shore-normal azimuth. Real-time differential GPS is used to navigate back to the datum points for repeat surveys. If the datum point is lost, then a new geodetic GPS survey for vertical positioning is conducted. The ground surveys help in the understanding of shoreline change by providing the following: