Mies van der Rohe, the famous modernist architect of the 20th century, uttered the phrase, “Less is more,” to explain the basis of his design style. Which of the above images do you think is a Mies design? Although I don’t share the modernist disdain for ornament and surface decoration, I have to say that Mies’ dictum is admirably suited to cartography as well! Less information is often more data for the user, or at least, more useable data. Consider the two [...]
The Mississippi River drains a huge portion of the North American continent, and it happens that a lot of people live along its shores, from Minnesota to Louisiana. The Spring rains have been heavy and consistent, which added to the thaw of the winter’s heavy snowpack, has brought the river to its highest stages since the record floods of 1927 and the early 1930s. The Army Corps of Engineers, which has responsibility for ‘managing’ this natural hydraulic leviathan, has had [...]
Two hands that don’t quite touch, from the famous image of the creation of Adam on the Sistine Chapel ceiling. We, the viewers, make the final connection, but in database building, this sort of missing link is a disaster. Missing links can be a plague when building a GIS for a region, a city, or a port facility. They require lots of data representing what is to be found on the ground, and under it. Often, the best data is in [...]
With GIS and other software tools, we can map statistical data with ease. Some types have been used so many times they have become iconic … or boring. The image above was created with software online at Gapminder that is beautifully designed to allow all sorts of interaction. If you click on the image, you will be taken to a live version of the image that you can drag through the decades to observe trends. This sort of experimentation raises fascinating possibilities [...]
There is excellent example of the perils of using powerful mapping software without a good grasp of basic cartography in the latest edition of ESRI’s ArcUser magazine. A brief article highlights a map from a news magazine several years ago that purported to show the portions of the Earth that were within striking range, 10,000 km, of a certain class of ballistic missile if it were fired from North Korea. The map seriously under-represented the area in peril because the cartographer had simply created [...]
In his book, Cartographies of Danger, Mark Monmonier examines the topic of how maps have been used to illustrate hazards, and in the process, shows us how they reflect different notions of the nature and proper way to assess risk. It is a topic that brings into full relief the power of maps to tell a story, and makes clear how careful cartographers must be about what story it is they want to tell. With a little web-surfing and a [...]
We all know that the map is not the terrain, but what is the terrain? When we need to know for a GIS exercise, we build a model, a DTM (digital terrain model) or DEM (digital elevation model). Of course, the terrain doesn’t have to be the surface of the land – it can be the variation in value of houses, incidents of a disease, or estimated population of an insect pest. The point is, a terrain surface is generated [...]
GIS is the union of maps and databases, often in the service of calculation. Economists, social scientists, hydrologists, engineers and others use it to include space, or distribution, into their attempts to explain natural or social phenomena. It is useful to keep in mind that this has been going on for a long time, more or less since the start of the Scientific Revolution. Tools and techniques change, but the governing ideas often do not, and the ideas are what [...]
The old hacker’s slogan is “Data wants to be free.“ And the retort is always, “Data wants to be expensive, because it’s so valuable.“ In the world of digital mapping and GIS, we run the gamut from the free to the very expensive when it comes to highly accurate data. To make matters more complex, there are issues of intellectual property involved, which makes themselves felt as licenses. As an example of this situation, consider Halcrow’s use of the UK [...]
The Earth may not be flat, but it is not perfectly round either. We say that it approximates an ellipsoid, a mathematically defined shape that is similar to a somewhat squashed sphere – bulging at the equator, flatter at the poles. GPS satellites are in orbit about the centroid, the center of mass, of this defined ellipsoid (sometimes called the spheroid), and the vertical measures they produce are all referenced to this simplified figure of the Earth. Too bad it [...]