Legacy biodiversity data from natural history and survey collections are rapidly becoming available in a common format over the Internet. Almost 100 million records are being served from the Global Biodiversity Information Facility (GBIF). However, our ability to use this information effectively for ecological research, management and conservation lags behind. One solution is a web-based Geographic Information System for visualization and analysis of these biodiversity data. This paper reports on a case study system developed for deployment at distributed database portals. The system, GBIF-MAPA (Mapping and Analysis Portal), allows users to explore worldwide biodiversity data and then perform a set of analyses including summarizing species richness for taxonomic groups of interest. Technical and research challenges included: assuring fast speed of access to the vast amounts of data available through these distributed biodiversity databases; developing open standards based access to suitable environmental data layers for analyzing biodiversity distribution; building suitably flexible and intuitive map interfaces for refining the scope and criteria of an analysis; and building appropriate web-services based analysis tools that are value to the ecological community. The results manifest the value of online biodiversity GBIF data. After discussing how we overcome these challenges, we provide thoughts on the future for web based biodiversity data acquisition and analysis.