Maps and Web-based Data - Participatory Mapping: New Data, New Cartography - page 68

Another technical constraint is related to the rate at
which the data are published online and can cause a delay in
their processing and display by the application. For instance,
the map “Crimespotting” (Table 4.1, map no. 2) depends on
the rate at which the data are made available by the San
Francisco police reports on criminal activity. As updates are
not added daily, after a few days without any new data, the
map remains empty as seen on the print screen in
Figure 4.7. The time of the last update is indicated at the
top-right of the page to account for the state of the map.

Mapping applications rely on the changes made to their
base maps but also to their data sources. A change in the
one,

the other or both may result in a dysfunctional

application.

Figure 4.7. “San Francisco Crimespotting”, Stamen Design, shows that the
police's last update was published five days before

Moreover, the maps are often made operational at the cost
of some technical bricolage. The London underground map
(Table 4.1, map no. 17, Figure 4.3) illustrates this notion.
Matthew Somerville explains his application on the

right-side ( What is this? ) and highlights the possible

technical errors: