Tag Archives: Differential geometry of curves

From SVG to Geo Coordinates – A Complete Guide

Why This Task Is Not Trivial?

First of all what do we have? There is a vector shape, which may represent a map, which we’d like to convert into a GEO map. In other words there is a SVG file containing the source shape, that you’d like to convert in geoJSON or whatever collection of geo points. This is not trivial, of course, first of all because there’s no an algorithm or automation that can do this, and because everybody knows that the resulting map will be only approached, but will never be so accurate as the vector shape. This is because in a vector shape you may contain Bézier Curves, which I’ll show a little bit later in this post, that are difficult to represent in geo coordinates.

So the first task will be to find an approaching algorithm. However there are two things that are optimistic:

  1. You can’t effectively represent Bézier curves in geo coordinates, but even if you could do it there’s no practical need, because the collection of geo coordinates will be huge and this will slow down you’re application. Remember that geoJSON is yet again possibly used by your browser and the amount of geo points will be proportionally slowing down the app.
  2. As you may know Google’s visualization map is representing the World’s countries again with quite approached maps. Take a look at the following image – the country borders are quite sharpened:

Google Visualization Map

So far we know that we need an approaching algorithm that will convert vector lines and possibly curves in geo coordinates, but before we proceed we’ve to understand the SVG format. Continue reading From SVG to Geo Coordinates – A Complete Guide