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 |
|
Conterminous U S (lower 48 states): NAD83(86) to NAD27 |
grids\conus |
|
Alaska, incl. Aleutian Islands: NAD27 to NAD83(86) |
grids\alaska |
|
Alaska, incl. Aleutian Islands: NAD83(86) to NAD27 |
grids\alaska |
|
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 |
|
St. George Is., AK: NAD83(86) to OLD ISLAND DATUM |
grids\stgeorge |
|
St. Paul Is., AK: OLD ISLAND DATUM to NAD83(86) |
grids\stpaul |
|
St. Paul Is., AK: NAD83(86) to OLD ISLAND DATUM |
grids\stpaul |
|
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 |
|
Hawaiian Islands: NAD83(86) to OLD HAWAIIAN |
grids\hawaii |
|
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 |
|
Guam: NAD83(93) to GUAM 1963 |
grids\guhpgn |
|
Hawaii: NAD83(86) to NAD83(93) |
grids\hihpgn |
|
Hawaii: NAD83(93) to NAD83(86) |
grids\hihpgn |
|
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 |
|
Michigan: NAD83(94) to NAD83(86) |
grids\mihpgn |
|
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 |
|
Samoa (Eastern Islands): NAD83(93) to AMERICAN SAMOA 1962 |
grids\eshpgn |
|
Samoa (Western Islands):: AMERICAN SAMOA 1962 to NAD83(93) |
grids\wshpgn |
|
Samoa (Western Islands): NAD83(93) to AMERICAN SAMOA 1962 |
grids\wshpgn |
|
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 |
|
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.
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 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.
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.
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.
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.
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 |