Desktop Mapping

Make the assumption a cartographer is producing a black-and-white map of Canada, with rivers, provincial boundaries and major cities, using a general purpose graphics program and a microcomputer. The first task is to input a base map. Today, base maps can be purchased in digital format, or perhaps downloaded from the world wide web. Another way to get a basemap is by using a scanner to convert an existing map, either a published map or a compilation, into digital form.

The scanned image is displayed on the screen as a grey backdrop, and then various graphics tools built into the program are used to trace in black the details to be included in the map. Other tools enable the mapmaker to add patterns, symbols and lettering and progressively builds up the map on the screen.

Color Mapping

Make the assumption a full-color atlas map of the land use of the Great Lakes Basin is going to produced. This, too, is produced by computer; the colors can be selected by a tool on the computer which colors lines and areas on command. Today’s high quality color printers reproduce colors very closely to the ones selected by the cartographer. If the final map needs to be printed or mass produced through offset lithography, the cartographer can provide the printer with a disk showing the color separations. Producing a color map used to be a lengthy painful process!

Mapping with Geographical Information Systems

The final case incorporates GIS analysis into the mapping process. A map is required of the Niagara Peninsula showing areas of tender fruit cultivation, located on sandy soils, between 100 and 120 m in elevation, and within 250 m of major roads.

An extensive digital database of the Peninsula already exists and contains maps (or layers) showing land use, soils and elevations. There is no roads layer, however, so the cartographer prepares his or her own from a published topographic map by using an electronic digitizer. The cartographer then embarks on a sequence of analyzes using the full power of the GIS software. From the land use, soils and elevations layers, three new layers are extracted, one containing tender fruit areas only, another sandy soils only and the third land between 100 and 120 m only. These are then combined by a process known as overlay to produce another new layer that contains only those areas that satisfy all three requirements simultaneously.

The final step is to use overlay once more to determine which of these areas lie within 250 m of major roads, though before doing this, the cartographer has to use a buffering operation to create a band 500 m wide along all the roads in the roads layer. The analysis is then complete, and the finished map appears on the computer screen, to be printed out if desired using some form of color printer or plotter.

What do cartographers do?

It goes without saying that most cartographers are employed in map-making, and the examples in the previous section give a good indication of the kind of work this involves. Individual cartographers vary a great deal in what they do, but we can identify certain basic functions that are performed by cartographers in general. The most important of these are liaison, editing, drafting, reprographics, administration, research, teaching and custodianship. Depending on the nature and size of the organization for which the cartographer works, he or she may perform just one or several of these functions. They are described separately below, but in reality there is often considerable overlap between them.

Liaison

Cartographers do not exist in isolation. They have frequent cause to interact and work with people from outside the profession, and this may occur at any stage in the mapping process. If, as often happens, the original idea for a map comes from someone else, the very first thing the cartographer does is discuss the client’s requirements in detail and draw up general guidelines for the project. And if the map is to be printed in full color, the very last responsibility may be to stand at the printer’s as the sheets come off the press to ensure that the printing is done to proper standards.

Editing

Editing encompasses a number of tasks, including the evaluation and processing of data, selecting scales and projections, making design decisions, drawing up flowcharts and specifications, preparing compilations, and last but not least, checking. Checking is very important indeed. Every piece of work done, no matter how minor–every line drawn, every name typed, every symbol positioned–must be independently checked and double-checked to ensure that no errors appear in the final map. In certain mapping situations, such as small-scale atlas cartography, the editing function is often assigned to a designated cartographic editor.

Drafting

This is the process of constructing the map image, which is, in general, done by computers, but it may also be done by hand, or by a combination of the two. Hand methods range from pen-and-ink work, supplemented by graphical aids such as dry transfer symbols and lettering, and the other techniques described in the previous section. Some cartographers–often called cartographic technicians–spend most of their time doing this kind of work.

Administration

Whether maps are made by an individual working alone or by several people as part of an organization, there is always administrative work to be done. At the very least this involves tasks like cost estimating, scheduling, budgeting, and purchasing materials and equipment. Supervising the work of others is another important administrative role. In major mapping organizations there are those whose work is almost entirely administrative. These are cartographers at the top of the hierarchy, with responsibilities covering personnel management, long-term planning, project coordination, public relations, and so on.