# Review of Web Mapping: Eras, Trends and Directions
## 2 Background and Developments
### Requirements for Defining Web Mapping Eras
The third generation web mapping was spurred on by the development of the Asynchronous JavaScript and XML (AJAX) technology, which improved response times and paved the way for direct user interaction with the map. This made way for open-service application programming interfaces (APIs), which could be accessed and combined with user contributed data in the generation of mashups. Finally, the fourth generation was focused on virtual earth globes such as Nasa World Wind, Google Earth and Microsoft Bing, which provide users with a more realistic and immersive experience with a three dimensional Earth. The advent of these first public web services with global coverage of digital imagery opened up the geospatial world of mapping to the public community worldwide via the Internet. The ability to generate maps expanded well beyond the small group of web developers and mapping experts. As [PERSON] [27] points out, the result is that knowledge and interest in places of experience become the realm of the average citizen, no matter where in the world they are located. \begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**[PERSON] \& [PERSON], 2003** & **[PERSON], 2005** & **[PERSON], 2007; [PERSON], 2011** & \begin{tabular}{l} **[PERSON] \& [PERSON],** \\ **2012** \\ \end{tabular}  & \begin{tabular}{l} **Multiple Authors** \\ **over Various Years** \\ \end{tabular}  \\ \hline \hline \multirow{4}{*}{ \begin{tabular}{l} \(\bullet\) Static \\ map publishing \\ \(\bullet\) Static \\ web mapping \\ \(\bullet\) Interactive \\ web mapping \\ \(\bullet\) Distributed \\ GIServices \\ \end{tabular}  } & \ \begin{tabular}{l} GIS awareness - \\ free satellite \\ imagery, \\ disaster response \\ \(\bullet\) User response \\ \(\bullet\) Virtual \\ online \\ mapping services \\ \end{tabular}  &
\begin{tabular}{l} \(\bullet\) First generation \\ - static \\ Second generation \\ - dynamic \\ Third generation \\ - average tiling \\ \(\bullet\) Virtual \\Following on from [PERSON]'s [27] four generations of web mapping, [PERSON] [28] described a fifth generation built on cloud computing, rich Internet applications (RIA) and crowdsourcing. Rather than focusing on obtaining sufficient hardware resources and downloading desktop software, users can access cloud computing resources and services, which now include, for example, Amazon cloud storage and web services, Microsoft Azure cloud and ESRI ArcGIS Online. RIA refers to a web programming environment that provides a friendly user interface and access to powerful widgets and tools (e.g., Google Web Toolkit and Adobe FLEX). In fact, the focus on web mapping developments goes even further than information and people. It goes to the heart of people interactions and engagements at a global level. [PERSON] and [PERSON] [1] identify stages of web evolution based on the primary focus of the developments (see Table 1). The web first appeared as the web of documents, was then transformed into a web of people, and now is developed as the web of data and social networks. The latter transition of the web is focused on a stronger link involving people and data, namely the people-to-people interactions around information and knowledge, which includes community mapping, location-based and mobile activities, dynamic processes and interactions, etc., in geographic context.