The size and complexity of high resolution lidar topographic datasets can pose challenges for both endusers, as well as federal, state, and local agencies tasked with curating and delivering these open datasets. OpenTopography is an initiative supported by the National Science Foundation that strives to streamline hosting, discovery, and processing of lidar (and other topographic data), with webbased tools for data visualization, custom product generation, and advanced analysis such as hydrologic routing and topographic differencing. OpenTopography partners with state and national agencies to increase the visibility, usage, and return on investment of their lidar data collections. This presentation will focus on a casestudy that illustrates topographic change across the state of Indiana, based on OpenTopography processing and analysis of Indiana's 20112013 statewide, and 20162020 QL2 3DEP lidar datasets. In this study we process both statewide datasets to one meter resolution digital surface models (DSMs), and then use OpenTopography's tools for vertical topographic differencing to calculate topographic change statewide at one meter resolution. The presentation will discuss the workflow, implementation, and technical challenges, and will highlight the changes in topography, vegetation, and the built environment that are revealed when two statewide lidar datasets are differenced.

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