The Permafrost Discovery Gateway Portal: Enhancing online, pan-Arctic visualization and exploration of high resolution permafrost data
The Permafrost Discovery Gateway (PDG) project is building scalable cyberinfrastructure to help researchers understand the extent, spatio-temporal variations, and impact of pan-Arctic permafrost thaw and other phenomena. We present the PDG portal, an online application that provides interactive visualization, exploration, and access to geospatial permafrost data products derived from high-resolution satellite imagery (Big Imagery). The portal leverages many existing software technologies, and builds upon them using standard and emerging geospatial processing tools and techniques. The PDG portal is built using the open source DataONE Portal system to allow easy customization of the application. It provides multiple interactive viewers including the Fluid Earth Viewer, which enables global and regional visualization of Arctic data products over time, and a Cesium-based Imagery Viewer that facilitates exploration of pan-Arctic, sub-meter map products over time. A Plot Viewer is also planned that will facilitate interactive data analysis where researchers can produce their own 2D and 4D graphs from the derived Big Data layers being produced by the PDG machine learning workflows. We discuss our initial data layer example of pan-Arctic ice-wedge polygon data derived from sub-meter imagery and processed into both raster and vector tiles that allow for performant panning and zooming using the Imagery Viewer. We present the challenges of creating a generic workflow that can be used to prepare tile layers across multiple input data formats, the indexing involved in making the data accessible for analysis online, and the workflow needed to provide access to the original layer data for download and further analysis through a customized search interface for the NSF Arctic Data Center archive.