Datum Shifts Available in NADCON v4.2

 

Conversion Type

Conversion Path\File Name

For general comments, refer to “Comments for Conversion Types,” below.  Additional conversion-specific comments are indicated in this column.

Conterminous U S (lower 48 states): NAD27 to NAD83(86)

grids\conus

See Conterminous US and Alaska comments below.

Conterminous U S (lower 48 states): NAD83(86) to NAD27

grids\conus

See Conterminous US and Alaska comments below.

Alaska, incl. Aleutian Islands:  NAD27 to NAD83(86)

grids\alaska

See Conterminous US and Alaska comments below.

Alaska, incl. Aleutian Islands:  NAD83(86) to NAD27

grids\alaska

See Conterminous US and Alaska comments below.

St. Lawrence Is., AK: OLD ISLAND DATUM to NAD83(86)

grids\stlrnc

 

St. Lawrence Is., AK: : NAD83(86) to OLD ISLAND DATUM

grids\stlrnc

 

St. George Is., AK: OLD ISLAND DATUM to NAD83(86)

grids\stgeorge

See St George-St Paul Islands comments below.

St. George Is., AK: NAD83(86) to OLD ISLAND DATUM

grids\stgeorge

See St George-St Paul Islands comments below.

St. Paul Is., AK: OLD ISLAND DATUM to NAD83(86)

grids\stpaul

See St George-St Paul Islands comments below.

St. Paul Is., AK: NAD83(86) to OLD ISLAND DATUM

grids\stpaul

See St George-St Paul Islands comments below.

Puerto Rico and the Virgin Islands: PUERTO RICO to NAD83(86)

grids\prvi

 

Puerto Rico and the Virgin Islands: NAD83(86) to PUERTO RICO

grids\prvi

 

Hawaiian Islands:OLD HAWAIIAN DATUM to NAD83(86)

grids\hawaii

See Hawaii comments below.

Hawaiian Islands: NAD83(86) to OLD HAWAIIAN

grids\hawaii

See Hawaii comments below.

Alabama: NAD83(86) to NAD83(92)

grids\alhpgn

 

Alabama: NAD83(92) to NAD83(86)

grids\alhpgn

 

Arkansas: NAD83(86) to NAD83(97)

grids\arhpgn

 

Arkansas: NAD83(97) to NAD83(86)

grids\arhpgn

 

Arizona: NAD83(86) to NAD83(92)

grids\azhpgn

 

Arizona: NAD83(92) to NAD83(86)

grids\azhpgn

 

California above 37 deg. lat.: NAD83(86) to NAD83(92)

grids\cnhpgn

 

California above 37 deg. lat.: NAD83(92) to NAD83(86)

grids\cnhpgn

 

California below 37 deg. lat.: NAD83(86) to NAD83(92)

grids\cshpgn

 

California below 37 deg. lat.: NAD83(92) to NAD83(86)

grids\cshpgn

 

Colorado: NAD83(86) to NAD83(92)

grids\cohpgn

 

Colorado: NAD83(92) to NAD83(86)

grids\cohpgn

 

Florida: NAD83(86) to NAD83(90)

grids\flhpgn

 

Florida: NAD83(90) to NAD83(86)

grids\flhpgn

 

Georgia: NAD83(86) to NAD83(94)

grids\gahpgn

 

Georgia: NAD83(94) to NAD83(86)

grids\gahpgn

 

Guam: GUAM 1963 to NAD83(93)

grids\guhpgn

See Guam comments below.

Guam: NAD83(93) to GUAM 1963

grids\guhpgn

See Guam comments below.

Hawaii: NAD83(86) to NAD83(93)

grids\hihpgn

See Hawaii comments below.

Hawaii: NAD83(93) to NAD83(86)

grids\hihpgn

See Hawaii comments below.

Idaho-Montana East of 113 deg. lon.: NAD83(86) to NAD83(92)

grids\emhpgn

 

Idaho-Montana East of 113 deg. lon.: NAD83(92) to NAD83(86)

grids\emhpgn

 

Idaho-Montana West of 113 deg. lon.: NAD83(86) to NAD83(92)

grids\wmhpgn

 

Idaho-Montana West of 113 deg. lon.: NAD83(92) to NAD83(86)

grids\wmhpgn

 

Iowa: NAD83(86) to NAD83(96)

grids\iahpgn

 

Iowa: NAD83(96) to NAD83(86)

grids\iahpgn

 

Illinois: NAD83(86) to NAD83(97)

grids\ilhpgn

 

Illinois: NAD83(97) to NAD83(86)

grids\ilhpgn

 

Indiana: NAD83(86) to NAD83(97)

grids\inhpgn

 

Indiana: NAD83(97) to NAD83(86)

grids\inhpgn

 

Kansas: NAD83(86) to NAD83(97)

grids\kshpgn

 

Kansas: NAD83(97) to NAD83(86)

grids\kshpgn

 

Kentucky: NAD83(86) to NAD83(93)

grids\kyhpgn

 

Kentucky: NAD83(93) to NAD83(86)

grids\kyhpgn

 

Louisiana: NAD83(86) to NAD83(92)

grids\lahpgn

 

Louisiana: NAD83(92) to NAD83(86)

grids\lahpgn

 

Maryland - Delaware - D.C.: NAD83(86) to NAD83(91)

grids\mdhpgn

 

Maryland - Delaware - D.C.: NAD83(91) to NAD83(86)

grids\mdhpgn

 

Maine: NAD83(86) to NAD83(96)

grids\mehpgn

 

Maine: NAD83(96) to NAD83(86)

grids\mehpgn

 

Michigan: NAD83(86) to NAD83(94)

grids\mihpgn

See Michigan comments below.

Michigan: NAD83(94) to NAD83(86)

grids\mihpgn

See Michigan comments below.

Minnesota: NAD83(86) to NAD83(96)

grids\mnhpgn

 

Minnesota: NAD83(96) to NAD83(86)

grids\mnhpgn

 

Mississippi: NAD83(86) to NAD83(92)

grids\mshpgn

 

Mississippi: NAD83(92) to NAD83(86)

grids\mshpgn

 

Missouri: NAD83(86) to NAD83(97)

grids\mohpgn

 

Missouri: NAD83(97) to NAD83(86)

grids\mohpgn

 

Nebraska: NAD83(86) to NAD83(95)

grids\nbhpgn

 

Nebraska: NAD83(95) to NAD83(86)

grids\nbhpgn

 

Nevada: NAD83(86) to NAD83(94)

grids\nvhpgn

 

Nevada: NAD83(94) to NAD83(86)

grids\nvhpgn

 

New England (CT,MA,NH,RI,VT): NAD83(86) to NAD83(96)

grids\nehpgn

 

New England (CT,MA,NH,RI,VT): NAD83(96) to NAD83(86)

grids\nehpgn

 

New Jersey: NAD83(86) to NAD83(96)

grids\njhpgn

 

New Jersey: NAD83(96) to NAD83(86)

grids\njhpgn

 

New Mexico: NAD83(86) to NAD83(92)

grids\nmhpgn

 

New Mexico: NAD83(92) to NAD83(86)

grids\nmhpgn

 

New York: NAD83(86) to NAD83(96)

grids\nyhpgn

 

New York: NAD83(96) to NAD83(86)

grids\nyhpgn

 

North Carolina: NAD83(86) to NAD83(01)

grids\nchpgn

 

North Carolina: NAD83(01) to NAD83(86)

grids\nchpgn

 

North Dakota: NAD83(86) to NAD83(96)

grids\ndhpgn

 

North Dakota: NAD83(96) to NAD83(86)

grids\ndhpgn

 

Ohio: NAD83(86) to NAD83(95)

grids\ohhpgn

 

Ohio: NAD83(95) to NAD83(86)

grids\ohhpgn

 

Oklahoma: NAD83(86) to NAD83(93)

grids\okhpgn

 

Oklahoma: NAD83(93) to NAD83(86)

grids\okhpgn

 

Pennsylvania: NAD83(86) to NAD83(92)

grids\pahpgn

 

Pennsylvania: NAD83(92) to NAD83(86)

grids\pahpgn

 

Puerto Rico-Virgin Is: NAD83(86) to NAD83(97)

grids\pvhpgn

 

Puerto Rico-Virgin Is: NAD83(97) to NAD83(86)

grids\pvhpgn

 

Samoa (Eastern Islands): AMERICAN SAMOA 1962 to NAD83(93)

grids\eshpgn

See American Samoa comments below.

Samoa (Eastern Islands): NAD83(93) to AMERICAN SAMOA 1962

grids\eshpgn

See American Samoa comments below.

Samoa (Western Islands):: AMERICAN SAMOA 1962 to NAD83(93)

grids\wshpgn

See American Samoa comments below.

Samoa (Western Islands): NAD83(93) to AMERICAN SAMOA 1962

grids\wshpgn

See American Samoa comments below.

South Carolina: NAD83(86) to NAD83(01)

grids\schpgn

 

South Carolina: NAD83(01) to NAD83(86)

grids\alhpgn

 

South Dakota: NAD83(86) to NAD83(96)

grids\sdhpgn

 

South Dakota: NAD83(96) to NAD83(86)

grids\sdhpgn

 

Tennessee: NAD83(86) to NAD83(95)

grids\tnhpgn

 

Tennessee: NAD83(95) to NAD83(86)

grids\tnhpgn

 

Texas (East of 100 deg. lon.): NAD83(86) to NAD83(93)

grids\ethpgn

 

Texas (East of 100 deg. lon.): NAD83(93) to NAD83(86)

grids\ethpgn

 

Texas (West of 100 deg. lon.): NAD83(86) to NAD83(93)

grids\wthpgn

 

Texas (West of 100 deg. lon.): NAD83(93) to NAD83(86)

grids\wthpgn

 

Utah: NAD83(86) to NAD83(94)

grids\uthpgn

 

Utah: NAD83(94) to NAD83(86)

grids\uthpgn

 

Virginia: NAD83(86) to NAD83(93)

grids\vahpgn

 

Virginia: NAD83(93) to NAD83(86)

grids\vahpgn

 

Washington-Oregon: NAD83(86) to NAD83(91)

grids\wohpgn

 

Washington-Oregon: NAD83(91) to NAD83(86)

grids\wohpgn

 

West Virginia: NAD83(86) to NAD83(95)

grids\wvhpgn

 

West Virginia: NAD83(95) to NAD83(86)

grids\wvhpgn

 

Wisconsin: NAD83(86) to NAD83(95)

grids\wihpgn

 

Wisconsin: NAD83(95) to NAD83(86)

grids\wihpgn

 

Wyoming: NAD83(86) to NAD83(93)

grids\wyhpgn

 

Wyoming: NAD83(93) to NAD83(86)

grids\wyhpgn

 



Comments for Conversion Types

NADCON transforms coordinate values between two geographic coordinate systems known as “datums.”  To do so, NADCON uses a “conversion grid,” which essentially provides a transformation “bridge” between the two datums.  NADCON can transform any two datums for which a conversion grid is available.  Refer to the following for additional information regarding specific areas.

Hawaii

The Hawaii data was gridded at 1.5 minute increments and covers an area from 18 to 23 degrees north and from 154 to 161 degrees west.

There are two problems with the geodetic station information in Hawaii. First, on the south side of the island of Hawaii, there is tectonic deformation.  This deformation can be up to about 6 meters.  In order to create the NADCON grids, about 16 first and second order stations were rejected because they showed NAD 27 to NAD 83 transformation shifts that were out of line with the transformation shifts of other stations in the area.

Second, the Hawaii data was never on the NAD 27 datum, but was on its own datum (the "Old Hawaiian" datum).  However, there have been more than one "Old Hawaiian" datums.  All of the first and second order stations and many of the third order stations were on the same datum.  The transformation shifts of these stations were what were modeled for NADCON.  However, about 300 third order stations did not fit the rest of the data, presumably because they had never been adjusted to the same Old Hawaiian datum.  These stations were not used when the NADCON Hawaii grids were created.

St George-St Paul Islands

St. George I. and St. Paul I. are part of a region known as the Pribilof Islands.  There were two separate datums, one for each island, before NAD 83(86).  The old island datums differ significantly from NAD 27.  Data input into NADCON must be consistent with the identified transformation data sets.  The transformation of misidentified data can result in errors of hundreds of meters.

 

Puerto Rico and the Virgin Islands

Puerto Rico and the American Virgin Islands were based on the Puerto Rico Datum rather than NAD27 prior to NAD 83(86).  Although occasionally the datum is misidentified as NAD27, this area was never on the NAD27.

Conterminous US and Alaska

The Conterminous US  grids cover an area from 20 to 50 degrees north latitude and from 63 to 131 degrees west longitude.  The Alaskan grids cover an area from 46 to 77 degrees north latitude and from 128 to 194 degrees west longitude.  The Conterminous US  and Alaskan grids overlap between 46 to 50 degrees north latitude and 128 to 131 degrees west longitude.  In this area, the Conterminous US  and Alaskan grids agree within 2 centimeters.  For those cases requiring precision greater than this, the Conterminous US  grids are to be considered correct.

Michigan

During the analysis of the transformation grids for Michigan, a serious inconsistency was found in the positional shifts for the control on Isle Royale when compared with the mainland portion of the state. Investigation revealed that this was due to the fact that no HARN stations had been observed on the island, and that the existing horizontal control had poor geometric ties to the networks in Michigan and Minnesota.  The island is classified as a wilderness area by the National Park Service and will see little if any development.  Therefore, the data for this area was omitted in the development of the transformation grids.

Guam

The Guam data was never on the NAD 27 datum, but was on its own datum, the Guam 1963 Datum.These grids are only to be used in transformations involving that datum.   Additionally, unlike the HPGN grids created for various states in the continental U.S. and Hawaii, which represent the shift between NAD 83(86) and the HARN readjustment of the state, these grids are based on the shift from the Guam 1963 Datum directly to the HARN readjustment.  No grids were ever created for the Guam Datum to NAD 83(86) shift.

 

American Samoa

Like Guam, the Samoan data was never on the NAD 27 datum, but was on its own datum, in this case the American Samoa 1962 Datum.  These grids are only to be used in transformations involving that datum.   Additionally, unlike the HPGN grids created for various states in the continental U.S. and Hawaii, which represent the shift between NAD 83(86) and the HARN readjustment of the state, these grids are based on the shift from the old Samoan Datum directly to the HARN readjustment.  No grids were ever created for the Samoa Datum to NAD 83(86) shift.

The positional data for American Samoa is distributed over two clusters of islands separated by many miles of ocean.  The lack of control on which to base grids, which this separation represents, creates distortions unless the grids are split into two separate grid pairs.  Samoa (Western Islands) covers the Islands of Tutuila and Aunu'u.  Samoa (Eastern Islands) covers Ofu, Olosega, and Ta'u Islands.

Additional Information

 

If you have any questions as to what order station you are using please contact:

 

Ms. Cindy Craig 
N/NGS21

Telephone: (301) 713-3194

email: Cindy.Craig@noaa.gov