In this age of information where petabytes of data is generated every day, there is need to utilize this data to solve day-today problems encountered in the modern society. For this reason, Geospatial Information Systems (GIS) have become ubiquitous. The curation, data visualization on maps, geocoding of the same, and online deployment using web 2.0 technologies are user-generated content that are interactive and geo-located. Collectively, when GIS is delivered via internet technologies, it is termed web GIS. Over the years, Web GIS has evolved and gained prominence. This paper explores the structure of Web GIS, evaluates various methodologies currently employed by developers in the design, development and implementation of Web GIS systems and proposes a methodology for developing a standard Web GIS based on evaluation criteria.