It differs from twenty m to 100 m. Closer intervals are required if floor level differs abruptly. The cross- sectional line needn't be constantly be at ideal angles to the key line. This technique is Preferably fitted to highway and railway projects. Radial Line Approach আমরা সারা বাংলাদেশে আমাদের সার্ভিস https://contour-survey-in-banglad41020.creacionblog.com/32071733/contour-survey-in-bangladesh-can-be-fun-for-anyone