# Review of Web Mapping: Eras, Trends and Directions
## 2 Background and Developments
### Requirements for Defining Web Mapping Eras  
Figure 1 illustrates a brief history of major web mapping events along a timeline. The development of web mapping started right after the web was created, primarily in the form of published online maps, with the PARC Map Viewer being the first web-based map [16; 17]. Relatively, web mapping has come a short way since its beginning but has achieved the level that may not be imagined two decades ago, attributing mainly to the advances in web technologies. What follows in this section is a brief description of various attempts by authors to describe web mapping events and developments as generations or eras, as adapted from and further detailed by [PERSON] [18]. In terms of its development, the web has generally been identified by various authors using four generations termed Web 1.0 to Web 4.0 (and beyond) [19; 20]. Web 1.0, as the Hypertext Web, defined the first era of read webs, focused on retrieving information. The basic HTTP and HTML technologies were the primary means to disseminate online linked information according to the vision of [PERSON] [20]. Web 2.0, referred to as the _Social Web_, is a read-write web where users can interact collaboratively for content creation, modification and sharing [21]. Web 3.0 is also known as the _Semantic Web_ and focuses on enabling machine understanding of semantically structured data that provide users with more meaning and relevant information [22; 23]. [PERSON] [19] describes Web 4.0 as the ultra-intelligent agent that makes decisions as powerful as the brain to enable collaboration among communities. Although there are various attempts at describing Web 5.0, some naming it as the _Sensory and Emotive Web_[24; 25], it remains essentially undefined and speculative. Figure 1: Timeline of some significant web mapping events. The generations of general web development have laid the foundation for web mapping development, which has come through a number of distinct yet interconnected or overlapping stages. Table 1 summarizes previous characterized eras by various authors with respect to different web generations, if applicable. [PERSON] and [PERSON] [9] considered that early web mapping had gone through stages of static map publishing, static web mapping and interactive web mapping. [PERSON] [26] further approached the evolving world of web mapping by highlighting the major technology changes. Although only focusing on the year 2005, he identified three significant developments (see Table 1). Firstly, GIS awareness grew significantly among the general community fueled by the release of free satellite imagery on the one hand, and by occurrence of major disaster events on the other. Events in 2005 such as the South Asia Tsunami and Hurricane Katrina alerted the global community to the importance of using mapping and GIS technology to manage and respond to such events. A second significant development in 2005 highlighted by [PERSON] [26] was two new Internet technologies, namely AJAX and image tiling, both focused on increasing the response times of web maps for users. These technologies formed the foundation for the development of virtual globes and online mapping services, identified as the third major change by [PERSON] [26]. Included in this change were also the wireless location-based services resulting in mobile access to GIS and mapping technologies. [PERSON] [27] identified four generations of web maps based on the types of technologies underpinning the map (see Table 1). The first generation maps were static maps such as those pioneered by the Xerox PARC map server [16]. They were static maps embedded in HTML files with simple click access via hyperlinks. The hyperlinks gave users some measure of choice in selecting the maps for viewing. The next generation comprised dynamic HTML maps created on-the-fly using Java and ActiveX with the map user interfaces starting to appear similar to GIS interfaces at that time. However, functionality was limited to map browsing and simple queries.