Conservation of the lowland savanna ecosystem in Belize Project (Defra 17-022) has created a database of savanna plant collections in the country. Some of the collections have accurate positional coordinates measured by GPS devices while the others’ locations are labelled with imprecise coordinates or locations written down descriptively. This study is an innovative attempt to develop a web-GIS system which conducts spatial queries on these collections whose positional qualities vary from accurate to meaningless. First, a fuzzy point model was created for points whose exact locations are unable to be specified. Second, the poor quality or absence of legacy collection coordinates was complemented by interpreting the locational description into the fuzzy point model. Then, a model for point-in-polygon analysis over the fuzzy point model was defined and implemented taking advantage of existing spatial database technology. Finally we achieved to create a prototype of online environmental GIS service which queries on both accurate and vague points in the same way and visualises them on maps within a tight timeframe generally allowed for web-based services.