august 2006 archives

Friday, August 18, 2006

100 Thematic maps

Launched a few months ago, but only recently brought to my attention is the 100 Thematic Maps website. The website reveals the history and achievements of thematic cartography through maps of the Netherlands. For example, there is the first choropleth map produced in the Netherlands (1827), the Kaart van het analfabetisme in het Koninkrijk der Nederlanden by Adolphe Quetelet. The oldest map is a map of the city of Utrecht by Jacob van Deventer and dates from 1569. The most recent map is a soil map published in 1994.

Let's hope the website becomes as popular as Oddens' Bookmarks maintained by the library's map curator. By the way, I am not sure whether this message on the Map Room's website is such a good idea: Due to a conference abroad no map curator will be present...  permanent link for this entry

Saturday, August 05, 2006

Epidemiology and the need for a GDI

Today's edition of the Dutch newspaper Trouw features an article on how the Amsterdam Local Health Authority used Google Earth to pinpoint the source of a recent outbreak of Legionnaires' disease. Inserting pushpins in a wall chart of the city, — thus marking the addresses of the people that were infected — the search area was first narrowed down to the eastern part of the inner city. Using Google Earth, the authorities then quickly established the locations of nearby cooling towers of air conditioning systems. Since these cooling towers are typically located on roof tops, they can be easily spotted on large scale satellite imagery. Water samples of all the suspect cooling towers were tested to single out the source of the outbreak: the one of top of the former post office next to the Amsterdam Central Railway station.

Epidemiology has a long history of using maps in determining the source of an outbreak. Today's article reminded my of a classic example: John Snow's map of the Soho area highlighting the cases of cholera in the London epidemic of 1854. His study of the distribution of cholera cases led to the source of the disease, a contaminated water pump within the heart of the outbreak.

The Dutch National Atlas of Public Health proves that geography is still an important factor in setting a national public health policy. Furthermore, various Regional Health Authorities in the Netherlands use online mapping tools to visualise public health indicators, e.g. the Public Health Atlas of Noord-Brabant and Zeeland. While these online atlases highlight the importance of geographic information in the policy making process, today's article shows that geographic information may play an important role in the operational processes of health authorities.

However, should a local health authority actually have to rely on satellite imagery provided by a global corporation, in this case Google, to battle future outbreaks? I guess it's a perfect showcase to once more convince people of the need for a Geographic Data Infrastructure (GDI), both on a local and a national scale. The Amsterdam Municipal Geo-information Department and the Netherlands' Topographic Survey presumably have more recent aerial imagery of the city, but it's the infrastructure to get it out to potential users that's still insufficient. On the other hand, let's be careful not to repeat the troubles that accompanied the launch of Geoportail, a mapping portal from the French national mapping agency IGN  permanent link for this entry