My boundary with a neighbor is a straight line defined by 2 permanent surveyor stones. They are the cement square columns set into ground where only to (+) shows at ground level. Said neighbor looked at GIS online and now thinks the boundary is wrong and has a surveyor coming out to do an A-2 survey. Aren’t the surveyor stones what will be used as a known starting point? Should I be concerned?
Please share your location with us so those commenting can make a superior judgement before responding.
Every GIS I have looked at has a disclaimer saying it is for identifying parcel owners and not controlling for boundaries. In most areas the GIS was not based on survey data, but only on trying to fit together the parcel deed descriptions, and laying them on a photo, with whatever accumulated error happens to occur. Your neighbor needs to recognize this.
Most surveyors will check that the existing monuments appear to be the original ones and if they seem to be undisturbed will hold those monuments over any more precise measurements.
There are, unfortunately, some few surveyors, or their poorly supervised employees, who will pick some corner they think must be right and use measurements that are more precise than the original accuracy with which the parcel was described in a deed. Your fear should be that he might get one of those unfortunate surveyors, or that if the surveyor does agree with the monuments the neighbor refuses to believe it.