State merits and demerits of plane table survey.
1 Answer
Merits: 1) It is the most rapid method of surveying.
2)There is no need for field book as plotting is done along with the field work, so the problem of mistakes in booking field notes does not arise.
3) Plotted work can be compared with actual object whether or not they are properly represented.
4) There is no possibility of overlooking any important object.
5) There is no possibility of overlooking any measurement as plotting is done in the field.
6) Irregular objects may be represented accurately.
7) It is suitable in magnetic area.
8) The maps can prepared easily and does not require any great skill.
9) Errors in measurement and plotting can be detected by check lines.
10) Inaccessible points can be easily located by intersection method.
Demerits: 1) The plane table is not suitable for accurate work as the fitting arrangements is not perfect.
2) Plane table surveying is not suitable in wet climate, rainy season, on foggy mornings and in windy weather.
3) The number of accessories required in such survey is large and they are likely to be lost.
4) The instrument is very heavy and difficult to carry.
5) The map cannot be replotted to defferent scale as there is no field book.