While crawling our beloved web we usually want to bind objects to GPS coordinates so we know where they are. Czech republic is not like any other country. In Czech republic there is search engine more popular than google no kidding. This search engine is called Seznam. Seznam provides services like search engine, catalogues, maps and many others. Seznam maps use special coordinate system which uses x and y axis. We usually want to convert these to GPS position. It is possible with their API but who would call their API when you can easily convert these coordinates with simple program.
First thing we need to do is to convert these coordinates to UTM.
x1 = x1 * Math.pow(2, -5) - 3700000; y1 = y1 * Math.pow(2, -5) + 1300000; String UTM = "33 N " + x1 + " " + y1 + "";
When we have UTM standard it is easier to convert to any other coordinate system with use of libraries. I prefer this code CoordinateConversion.java
We can simply call this library:
double d = c.utm2LatLon(UTM);