CalGIS 2025

Now that we have LiDAR data, let’s put it to work improving our surface water maps.  Learn about tools available now for extracting information from the LiDAR digital elevation models, including geomorphic landforms, z-values, and more, to create channels that represent the presence and flow of water on the landscape.  Attendees who provide their own laptop and ArcGIS Pro license will be invited to follow along this demonstration of using a Geomorphic Index (GMI) to help identify the most likely flow paths. This workshop includes fundamentals on the US Geological Survey’s National Map hydrography datasets: past, current, and future; from the NHD to 3DHP, and the role of federal, state, regional, and local entities in building out a modern hydro network for the Nation.

Key takeaways: Our collective investment in LiDAR is paying off by enabling the creation of hydrography that has improved horizontal accuracy and alignment with the earth’s surface. While the USGS has taken the lead in the acquisition of elevation-derived hydrography for its nation-wide 3D Hydrography Program, the build-out of this hydrography network will take several years. In the meantime, GIS practitioners can replace legacy datasets for their own geographies of interest with LiDAR data and tools that may already be available to them. This hydrography can be put to good use for their mapping and modeling needs.

Attendees should bring their own charged laptop and ArcGIS Pro license in order to follow along.