@kevin-hines It's not always 1 foot. Sometimes 0.1 foot, once 4.9 foot. I basically know where the data comes from to get a OPUS derived elevation. No...

@kevin-hines That's ridiculous. Floodplain boundaries and Base Flood Elevations we're not created by means to develop elevations to a 0.1 of a foot. ...

@rover83 Statistics! I think statistics should be used to evaluate the accuracy of a benchmark, not establish it. I misunderstood your use of Ortho. ...

@mightymoe There are no benchmarks referenced on the newer 2013 era FIRM maps or anywhere else in the FEMA documentation. The older NAVD29 maps did ha...

@norman-oklahoma I have more trust in the OPUS Elevations. Redundant measurements have always matched within .003 meters. The error analysis done by O...

@norman-oklahoma The geoid model has something to do with it I believe. That's another statistical use of a computer to come up with finite answers.

@rover83 What purpose would an Ortho have in establishing a NGS benchmark? The benchmarks were established years before Orthos were developed. The be...

@olemanriver There is about 3 foot difference in NGVD 29 and NAVD88. I have found two NGS monuments to differ by over 4 feet between the monument ver...

@andy-j Craig, Montana. There is regularly a foot of difference in checked NGS monuments comparing between two monuments.

@jim-in-az Now logically thinking. Do you think that's what they were thinking? Don't think like a lawyer, use some common sense.

@holy-cow Sometimes it's 12 inches under a County road. After digging for an hour chipping away with a digging bar finding a little piece of flagging ...

@holy-cow I always leave what I call Surveyor:s scent, red flagging at every corner I find. You calling me ego-centric? ????

@holy-cow just teasing

@williwaw He never set one monument.He identified the Meander Corner brass cap as also same as the Government Lot corner. The Tax Map (GIS) person us...

@williwaw The surveyor just used the GLO Plat's and a USGS 7-1/2 minute quad.. Used the Plat dimensions and scaled the dimensions not on the GLO Plat'...