Digital Map Products and the GIS Revolution

A typical map storage facility. This one is from the US Library of Congress (photo Beatriz M Haspo, 2011)

There will always be a place for paper maps because sometimes computer displays are impractical or unavailable. Besides, many people prefer paper maps over digital maps. A big issue with paper maps has always been that they are not customized to the purpose that they’re being put to, and where traditional production techniques are used they can be out-of-date.

Producer defined maps

Paper maps have traditionally been used for giving people a general thematic picture of the world, but these maps have mostly been ‘Producer defined’, meaning that the producer of the map (eg. government department) has defined which areas would be mapped, the data that would be included in them, and the scale that they would be represented. The traditional way of producing maps is to produce very generalized, general-problem maps – maps that suit as many different users as possible. This means that…

  • very specialized users have to make-do with what data are available, and
  • general users often have to make-use of maps with more data than required (which can be confusing for novice users).

User defined maps

In contrast, when Mapping Agencies make GIS maps available, users can produce very focused maps, effectively making their own digital maps products.

For example, one person might want a map with only roads and water courses on it, and another might want a map with roads, property boundaries and telephone boxes.

Maps on demand

These days GIS can produce similar sorts of output that traditional cartographers could. But GIS is far more effective in the way it stores and retrieves spatial information. In 1993 my 4th year university thesis was partly sponsored by the State Mapping Agency in my home town (Victoria, Australia).

I remember being taken on a tour of the back-room and seeing piles, and piles and piles printed maps. There were hundreds of copies of some maps and tens of copies of most. The Agency printed those in batches every 2, 3, 4 or 5 years depending on demand. However, important maps with little demand might get reprinted with updates years apart.

So, for example, fire services might find themselves in emergency situations with out-of-date maps. With GIS, assuming that an Agency has a map maintenance regime in place, now we can have on-demand printing of the latest version of each map. And every time someone requests a map sheet, you just go off and print it for them. This means that

  • there’s no need for expensive map storage in a fully implemented system.
  • The latest version of a map would always be available

Adjoining map tiles

And finally, one of the things that gets in the way so often has been map tile boundaries. Traditionally, if your field area was at the edge of 2 map sheets you had to sticky-tape the maps together.

In contrast, in a GIS you just display or print the area that you’re interested in. Here’s an example of a number of well known digital map products – think of Google maps – you don’t encounter map tiling problems there!

I hope you found this article helpful. Let me know in the comments if you still have questions.

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