what do you mean by pilot survey.what is it role in successful operation of a field of survey ?

Pilot surveys are the preliminary or the initial research tasks that are undertaken before the commencement of the actual survey. These surveys are conducted basically to access the effectiveness and efficacy of the research methodology (rules, postulates, principles, formulas, sample-study, etc.). The significance (or the role) of these surveys is to make the surveyor aware and alert of the probable difficulties that he might face while conducting the actual survey. Also many times, it may happen that some challenges and problems go unnoticed (or are unanticipated) at the time of research proposal stage. Pilot surveys do take care of these problems, thereby, ensure the success of the actual survey.