Salt marshes are critical habitats, but their persistence is threatened by relative sea level rise and erosive forces. To predict the fate of salt marshes, salt marshes are frequently mapped and tracked over time. There are many approaches to mapping salt marsh shorelines, but it is not clear how the underlying uncertainties associated with each mapping approach affect estimates of shoreline change. Furthermore, mapping technologies and data repositories have rapidly improved, but the underlying data uncertainties have been poorly described.
Our work demonstrates how various approaches for mapping salt marsh shorelines affect shoreline change analyses. First, we compare various mapping approaches by characterizing their underlying errors. Next, we model scenarios of marsh shoreline change to examine how shoreline change estimates would differ by mapping approach under various scenarios. Finally, we compared shoreline rate estimates as determined from high-precision, in-field monitoring versus coarser, desktop-based approaches. Therefore, we specify the tradeoffs between mapping approach and quality of shoreline change estimates, helping end-users identify approaches most suitable for their local erosional environment. 
We synthesize and share these findings as a decision support tool to guide users toward site-specific, cost-effective monitoring of marsh shoreline change.