Joint Venture Survey

I received a call from a broker and request me to do joint venture survey for a piece of land. The issue I would like to emphasis here is a land with many owners in the title, a licensed land surveyor can not determine where is the portion of the particular land owned by the said person. If we look at the title, it clearly stated that the portion owned and no the actual hectareage. Thus, for this problem case, we always advise to do sub-division application to solve all the unnessary problem.