**In a nutshell: ** In web maps, geographical coordinates are projected as if the Earth were a perfect sphere. The results are great for general use but not for high-precision applications. Continue reading ‘Maps on the Web’

## Posts Tagged 'Maps'

### You Can Do Maths

Published March 19, 2015 Irish Times Leave a CommentTags: Applied Maths, Arithmetic, Education, Maps, Social attitudes

Bragging about mathematical ineptitude is not cool. There is nothing admirable about ignorance and incompetence. Moreover, everyone thinks mathematically all the time, even if they are not aware of it. Can we all do maths? Yes, we can! [See this week’s *That’s Maths* column (TM064) or search for “thatsmaths” at irishtimes.com].

### The Steiner Minimal Tree

Published January 29, 2015 Occasional Leave a CommentTags: Algebra, Algorithms, Gauss, Maps, Topology

Steiner’s minimal tree problem is this: **Find the shortest possible network interconnecting a set of points in the Euclidean plane.** If the points are linked directly to each other by straight line segments, we obtain the *minimal spanning tree*. But Steiner’s problem allows for additional points – now called Steiner points – to be added to the network, yielding *Steiner’s minimal tree*. This generally results in a reduction of the overall length of the network.

### New Curves for Old: Inversion

Published December 11, 2014 Occasional Leave a CommentTags: Analysis, Geometry, Maps

**Special Curves**

A large number of curves, called *special curves*, have been studied by mathematicians. A curve is the path traced out by a point moving in space. To keep things simple, we assume that the point is confined to two-dimensional Euclidean space so that it generates a plane curve as it moves. This, a curve results from a mapping . Continue reading ‘New Curves for Old: Inversion’

### Gauss’s Great Triangle and the Shape of Space

Published July 10, 2014 Occasional Leave a CommentTags: Gauss, Geophysics, Maps

In the 1820s Carl Friedrich Gauss carried out a surveying experiment to measure the sum of the three angles of a large triangle. Euclidean geometry tells us that this sum is always 180º or two right angles. But Gauss himself had discovered other geometries, which he called non-Euclidean. In these, the three angles of a triangle may add up to more than two right angles, or to less.

Continue reading ‘Gauss’s Great Triangle and the Shape of Space’

### Santa’s Fractal Journey

Published December 19, 2013 Irish Times Leave a CommentTags: Fractals, Maps

The article in this week’s *That’s Maths* column in the* Irish Times* ( TM035 ) is about the remarkable Christmas Eve journey of Santa Claus.

### Ireland’s Fractal Coastline

Published December 12, 2013 Occasional Leave a CommentTags: Fractals, Ireland, Maps

Reports of the length of Ireland’s coastline vary widely. *The World Factbook* of the Central Intelligence Agency gives a length of 1448 km. The *Ordnance Survey of Ireland* has a value of 3,171 km (http://www.osi.ie). The *World Resources Institute*, using data from the United States Defense Mapping Agency, gives 6,347km (see Wikipedia article [3]).