Dengue is the world's most rapidly spreading and geographically widespread arthropod-borne disease which needs proper surveillance and control strategies. Effective detection and containment of dengue has proven to be challenging due to the complex nature of interactions among the governing epidemiological factors as well as a number of environmental, climactic and societal attributes. An interactive approach of visualization and mapping of dengue cases on Google Maps is proposed here for the purpose of disease monitoring and surveillance. Our dengue visualization system is a web based application. It is developed using the Shiny package of R software along with HTML and JavaScript interfaces. Malaysia has the two types of databases for dengue: the e-Dengue database for registered cases and the e-Notifikasi database for notified cases. The e-Dengue database has latitude and longitude information, obtained manually, for each registered dengue case. The visualization system uses those latitudes and longitudes to plot the registered cases on Google Maps. Notified cases do not have any latitude and longitude information but have a case location address for each case. Automatic batch geocoding of addresses is developed for notified cases. Subsequently, notified cases are rendered on Google Maps separately or together with registered cases to gain an understanding of the statistics of disease spread. Filtering options are developed according to either the notification or registration dates. The dengue geocoding and visualization system, DenMap, is an interactive and easy-to-use application for producing maps of notified and registered cases rapidly. The maps display accurate locations of dengue cases and can be made to render other information of each case using map markers. This visualization and analysis system will not require any technical expertise for its usage. © Published under licence by IOP Publishing Ltd.