Cartography

In the period up until about 1985, the various different roles of professionals in topographic mapping were clear and obvious. The geodesist made the detailed instrumental readings and computed results which defined the basic shape of the country (see Geodesy). From this information, land surveyors filled in detail on the ground or photogrammetrists provided mapping using aerial photography. Cartographers compiled their efforts into an attractive form which met high standards of graphic elegance and communicated the information effectively and unambiguously. Other collectors of geographic information such as geologists or soil surveyors used these maps as a base on which to collect other details of interest to them. They also formed the outline base map for statistical thematic mapping.

This cosy and stable structure was rocked by the advent of new technology. Much highly skilled work has been replaced by the introduction of the Global Positioning System (GPS) satellites, new surveying equipment, and technology in general. The boundaries between the separate roles became blurred as field workers accessed their databases remotely; software mapping functions improved and the non-specialist became the “new mapmaker”.

But it is quite wrong to think of this as a declining industry, in fact totally the opposite is true. The development of the set of tools called a Geographical Information System (GIS) has transformed the geographic information-based professions. The separate roles of geodesist, surveyor, cartographer, geographer, and all users have come together to form a “new” discipline, Geographic Information Science (sometimes GeoInformatics or Geomatics). The original GIS, built in Canada in 1965, consisted of an inventory of the state of the fauna and flora across the country. Nowadays, systems are in use around the world, linking and holding data and metadata on an extensive range of subjects. Innovative exploitation is expanding daily, enhanced by worldwide communication facilities.

The range of tasks that the Geographic Information Scientist may be called on to answer is infinite if we consider all the details of what goes on in different human activities, such as marketing a product to a target audience; storing details of every utility cable in a nation; recording every land transaction; or modelling global change—GIS tools are involved in all of these and many more. It is helpful, however, to summarize the capabilities as being able to answer the following generic questions:

• What is at ...? (for example, What type of soil exists at latitude X, longitude Y? or What is the population of the prime minister's parliamentary constituency?)
• How do I get from ... to ...? (for example, Give me detailed instructions for driving from Regent Street in London to the Place de la Concorde in Paris)
• Where is ... true/not true? (for example, Where in the country (or the world) can I find crop type A grown on soil type X?)
• What has changed since ...? (for example, How much change has there been in rainforest extent in the past 20 years?)
• What spatial pattern(s) exist(s)? (for example, Where—if anywhere—are there geographical clusters of deaths among children due to cancer of a particular kind?)
• What if ...? (for example, What if we added another feeder road to the orbital motorway around the capital city? How much would traffic increase and where would the changes occur?)

Modern GIS has a great advantage. The system can bring together geographical information collected separately by different organizations. Typically these collect information for their own purposes and the only relation to other organizations is through geography, that is, location. Using this location information (latitude and longitude or grid coordinates), the GIS “overlays” one data set on top of another and computes the characteristics of common areas. If there are two data sets (such as soils and crop productivity) for a country, we have one combination. If, however, there are 20 different data sets, there are 190 pairs in combination and over 1 million combinations in total. Much effort is expended in developing compatible or even better a single data specification standard for use in recording, transferring, and processing spatial data. Such are the characteristics of spatial data including definition of point, line, and area relationships that it requires an extensive system definition.

Geographic Information Science has already had an impact on cartography. In the first place, it is a positive development for national mapping organizations like Ordnance Survey, because it ensures and encourages wide use of the organization’s data. But the effects are much wider. For instance, the traditional map, while it can hold huge amounts of information in a compact space and is most convenient for use in the field, is difficult to use as an analytical tool. A digital database on the other hand can be queried and different kinds of information extracted, combined in a meaningful way, and its display tailored to individual needs. Then again, the map remains an unrivalled way of depicting variations in geography such that many people can readily understand. The extension of the GIS toolbox, that is, the “information sifting and exploring engine”, to include better cartographic capability, is ensuring a revival and expansion in the use of mapping—new users are exploring and experiencing the skills and knowledge of traditional cartography and even the paper map is still in demand.