简介:Inthispaper,theauthorsputforwardabriefandpracticalarithmeticforautoextractingterrainlinesfromdigitalterraindataafteranalyzingandcomparingcurrentarithmetics.Thispapergivesanexperimentresultthattheridgeandvalleyextractedbythearithmeticisconsistentwiththeexperimentalterrain.