I tried to generate contour line map ( level set, isopleth, isoline, isogram or isarithm) for Biela stopa (White trail), which is 48 or 25km cross-country ski (free technique) competition with mass start, which will take place this year Sunday, 11. February 2007. registration fee is less then 28 EUR. App 1000 people are expected. Details on:
http://www.bielastopakremnica.sk/