Towards an EBV Analyzer based on VAT
The Essential Biodiversity Variables (EBVs) proposed by GEO BON offer great benefits for decision makers and scientists if they are made readily available. Currently, the usage of EBVs is, however, still a challenge. The required data sets are very large, heterogeneous and temporal. This makes the usage in common tools like GIS very cumbersome. We propose the VAT system, a web-based processing engine for spatio-temporal data, as an ideal tool for EBV visualization and analysis. VAT is being developed as part of GFBio, but was designed to work independently from the start. Here, users can access a rich set of environmental layers and combine them with their own, private data. So-called exploratory workflows allow users to process data in an interactive fashion while guaranteeing reproducibility of the result. In cooperation with GEO BON we are working towards using VAT as the future EBV Browser & Analyzer. In our first use case we considered the global forest change EBV that measures the yearly global loss and gain of tree cover. In particular we wanted to investigate the change over time for a given region of interest. This information is highly relevant for decision makers as well as scientists. In our application users can choose between forest loss and forest gain and then specify their region of interest. This is either done by selecting a country from a list, or by drawing a custom polygon on the map. The relevant part of the EBV data set is added to the map as a new layer. In addition, a plot visualizes the aggregated changes over time. On the technical side this requires intersecting the raster data from the EBV with the user-defined polygon. The size of the raster makes it necessary to work with overviews in order to achieve a low-latency computation. For plotting the temporal development, we make use of our interface to R which allows us exploiting its powerful plotting functionality. In our ongoing work we will implement a public EBV catalogue that allows users to search and submit EBVs. Quality indicators will assist users to decide on the suitability of the data for their given use case. The data from the EBV catalogue will be available in the VAT system for scientists. In addition, VAT also offers simplified report views that hide the complexity of the actual computations and are thus suitable for decision makers and even the general public.