This paper presents an approach for an extensible web mapping customisation system for the Gazetteer for Scotland (GfS) based on Google map techniques. An analysis and discussion on the user feedback comments demonstrates that the information data source on the GfS website is too huge to be used for the average user, which has caused a big users inconvenience. To address this problem bringing much convenience for the users of the GfS to explore the information of Scotland on the GfS website, the developed system tries to find a way with functions to allow users to collect the data they are interested and to generate the data onto a personal map. Particular issues relating to the task of mapping customisation of the GfS as a data source to help users to make effective personal maps are discussed in association with the available technologies. By using suitable technologies chosen in base of a comparison and discussion between the available current ones, this system was designed and tested. The design details on the theoretical principle, data generation and implementing process of this effective system are described in this paper. Figures are given to illustrate the method and to help users to understand the new system. A short discussion is mentioned to further improve this system.