Illegal to sell dimension/volume/contour/elevation maps in the NY,NJ area without a licensed surveyor?

Hello, 

I am exploring the possibility of selling “non-survey” grade data such as rough dimension estimates, volume calc, contour/elevation maps. 

I was told by an engineer that it is illegal to sell any measurement in the NY, NJ area without a licensed surveyor’s stamp. 

Is it this true? Can any verify this claim?

Yes, this is correct.  Depending on the state, you either need to be a licensed surveyor or engineer.  Check with the engineering and/or surveying board in that state to see what constitutes surveying and mapping.  In general, you have to be a licensed surveyor (or possibly engineer) to perform volume calculations as a service in the US.