State Highpoints Converted to NAVD 88 Data (Delaware Big Loser — 1 Foot and Colorado Big Winner + 7 Feet)

I have converted state highpoint heights to the from NGVD 29 to NAVD 88 data using the USGS Verton calculator.

Interestingly Delaware rather Florida is the big loser in the conversion (the difference in height reflects a 1988 discovery that gravity should have be factored in the 1929 standards for measuring elevations).

Predictably the big mountains all had dramatic increases with Colorado’s Mount Elbert increasing almost 7 feet — it’s conversion was higher than the slightly higher Mount Whitney in California because Whitney is closer to the ocean and thus loses out on the mass calculation.

Read more about the conversion process (and either download the converter or do it online.

The convertor does not calculate Mount McKinley or Mauna Kea because the conversion process is very involved (it is not a clean cut addition to an Excel formula) and the USGS does not have the funding or time to calculate the rest of the U.S. or the world. The look up tables for just the U.S. for the formula are nearly 3 megs!

The table in the second column show current NVGD data rounded to feet, third column shows the heights rounded to feet after the conversion. The fourth column shows the difference in feet after the conversion and the fifth column shows the difference in inches.


State Highpoints Converted to NAVD 88 Heights
State NGVD 29 NAVD 88 Difference Feet Difference Inches
Alabama 2407 2407 0.3 3.1
Alaska 20320 20320 0.0 0.0
Arizona 12633 12637 4.4 53.0
Arkansas 2753 2753 0.2 3.0
California 14494 14500 6.1 73.5
Colorado 14433 14440 6.5 78.5
Connecticut 2380 2379 -0.6 -7.8
Delaware 448 447 -1.0 -12.2
Florida 345 345 -0.2 -1.9
Georgia 4784 4784 0.2 2.0
Hawaii 13796 13796 0.0 0.0
Idaho 12662 12668 5.5 66.2
Illinois 1235 1235 -0.2 -2.3
Indiana 1257 1257 -0.4 -5.3
Iowa 1670 1671 0.7 8.4
Kansas 4039 4041 1.6 19.2
Kentucky 4145 4145 -0.3 -3.2
Louisiana 535 535 -0.2 -2.6
Maine 5267 5267 -0.4 -4.9
Maryland 3360 3360 -0.4 -4.9
Massachusetts 3491 3491 -0.5 -5.7
Michigan 1979 1979 0.2 1.9
Minnesota 2301 2302 0.5 6.1
Mississippi 806 806 0.0 0.1
Missouri 1772 1772 0.1 1.1
Montana 12799 12804 5.1 61.8
Nebraska 5424 5427 2.7 32.1
Nevada 13143 13149 6.1 73.3
New Hampshire 6288 6288 0.1 0.7
New Jersey 1803 1802 -0.6 -6.7
New Mexico 13161 13166 5.4 64.3
New York 5344 5344 -0.1 -1.1
North Carolina 6684 6684 0.1 1.0
North Dakota 3506 3508 1.7 21.0
Ohio 1550 1549 -0.6 -7.4
Oklahoma 4973 4975 2.3 27.8
Oregon 11239 11243 4.4 52.4
Pennsylvania 3213 3213 -0.3 -3.6
Rhode Island 812 811 -0.8 -9.4
South Carolina 3560 3560 -0.1 -1.0
South Dakota 7242 7244 2.2 26.5
Tennessee 6643 6643 0.2 2.5
Texas 8749 8751 2.2 26.8
Utah 13528 13534 5.9 71.1
Vermont 4393 4393 -0.1 -1.8
Virginia 5729 5729 0.1 1.0
Washington 14411 14417 6.3 75.7
West Virginia 4863 4863 -0.2 -2.9
Wisconsin 1951 1951 0.1 0.9
Wyoming 13804 13810 5.7 68.5

In posting this one of the helpful links was an online csv to html converter (converting by saving an Excel file to an html table causes problems as Microsoft bloats the conversion). Interestingly this nifty feature has no backwards links at this posting. The site also offers the perl code to run it on your own server.


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