The purpose of this project will be provide topographic mapping of barrier islands and correlate tidal data into this mapping technique. This will allow small mammal researchers to determine island inundation during tidal storm highs which may lead to small mammal extinction or migration. Most other LTER research sites on barrier islands will be incorporated into the GPS data collections providing benefit to all researchers. Collected data will be ArcInfo compatible providing LTER, the Nature Conservancy and Northampton County with a useful tool.