The Tile-Based Mapping Transition in Cartography - Maps for the Future Children Education and Internet - page 153

MapQuest introduced its online mapping site in 1996 based on a large database
that included most streets in the North America. Within months, it was producing
millions of maps every day and was the leading online map provider until 2009. The
user's client computer would make a request for a specific map. MapQuest servers
would respond to the request by drawing the map from a database of points and
lines, converting this to a grid-based raster format and delivering the resultant map
within a web page.
Each request for another map, at a different zoom level or centered at another
point, would result in another server request that would produce another map that
would be embedded in another webpage that would update the page on the user's
computer. Although the process was fairly fast, there was always a wait for the
server to respond. A simple zoom or pan required waiting for the server to produce
another map that was inserted into another webpage. Server requests are also
subject to Internet traffic so a request for a map might take considerably longer
when traffic was heavy. Maps would be produced more quickly in the overnight
hours when Internet traffic was lighter. This variability in response times was found
to be more annoying for users than the generally slow response times. Figure 13.2
depicts a 2001 version of MapQuest along with three maps of southern Florida at
different scales.

13.3 Tiled Web Maps

Google Maps, introduced in 2005, offered a more interactive street map interface
(Peterson 2007 ). Google, known for its search engine, effectively added a map-
based search engine through Google Maps and the stand-alone Google Earth. In the
process, they found a more effective way to indirectly make money from online
maps by charging businesses, much like the way they make a profit through their
search engine. In addition, by not including ads around the map, like MapQuest,
they left more room for the map on the computer screen. Google Maps is based on
two major ideas: (1) image tiling; and (2) AJAX.

13.3.1 Image Tiling

Image tiling had been used since the early days of the World Wide Web to speed the
delivery of graphics (Sample and Ioup 2010). In comparison to text, images
require more storage and therefore take longer to download. A solution was to
divide the image into smaller segments, or tiles, and send each tile individually
through the Internet. These smaller files often travel faster because each can take a
different route to the destination computer. On the receiving end, the tiles are
reassembled in their proper location on the web page. With a moderately fast
Internet connection, all of this occurs so quickly that the user rarely notices that