Ski resorts 'exaggerate piste lengths' Using a digital mapping system, he measured the lengths down the middle of the pistes, following the slopes' twists and turns. These values were checked against information given to annual guidebook Where to Ski and Snowboard - and the majority of resorts, including some of the biggest in Europe, were found to be exaggerating the extent of their ski area by up to 150 per cent. Measured the Schrahe way, the Trois Vallées, France, oft quoted as the biggest ski area in the world, has 493km of pistes - still well above other ski areas - but 22 per cent less than official figures. The resort total of 4 Valleys, Switzerland, was found to be 198km above Schrahe's figure - a discrepancy of 120 per cent. Meanwhile, St Anton, Austria, was one of the report's saints, being only three per cent out. Schadming, also in Austria, was the only measured resort to say it's smaller than it actually is - claiming 121km, and having 131. Dave Watts, co-editor of Where to Ski and Snowboard, said: "We find it difficult to believe all these resorts are simply lying or mistaken about the size of their mountains, so we've made some attempts to find out how they arrive at these figures." The Grand Massif ski area in France, which includes Flaine and claimed 265km, while Schrahe measured 172km. "The lift company told us it measures its pistes in much the same way as Schrahe and gets an almost identical result, but it adds 57 per cent to take account of the fact you make turns rather than going straight down the slopes," said Watts. Schrahe's report has also been used to directly compare the size of European and North American resorts, since the latter measure their ski areas in acres. Schrahe found Whistler in Canada, North America's biggest ski area, has 252km of pistes, ranking it alongside Zermatt-Cervinia in Europe and joint fifth biggest in the world. Of the biggest areas in the US, Where to Ski and Snowboard revealed that while Big Sky/Moonlight has slightly more acreage (5532) than Vail (5289), Vail has slightly more km - 222km vs 215km. "What matters," said a Where to Ski and Snowboard spokesman, "is that resorts should measure their pistes in a standard way." And the editors are hopeful this might come about. The 4 Valleys is looking into the discrepancies and producing a report on its piste length, Austria's national association of lift companies has issued guidelines on how pistes should be measured, and some French resorts have also said that they would welcome standard guidelines. Saints Resort Claimed total (km) Measured total % exaggeration Kitzbuhel Lech-Zurs St Anton-Stuben Les Saisies Saalbach Sinners Claimed total Vars Isola 2000 Les Sybelles Follow Telegraph Ski and Snowboard on Twitter.