AutoCAD Map 3D toolset uses North American Datum Conversion (NADCON) grid data files from the National Geodetic Survey to obtain latitude and longitude shift information for converting between coordinate systems within the United States. A pair of grid data files is required for each area or state covered: a .las file is required for latitude shift values (latitude seconds) and a .los file for longitude shift values (longitude seconds).
The NADCON files include grid data files for transformations between NAD83 and state readjustments to HARN (High Accuracy Resolution Network) projects.
The .las and .los files are in the public domain and are distributed with AutoCAD Map 3D toolset. The files are stored in the Autodesk shared coordinate system folder. By default, it is located in C:\ProgramData\Autodesk\Geospatial Coordinate Systems.
The following is a list of NADCON grid data files.
| Files (.las and .los) | NADCON (North American Datum Conversion) | Area/State |
|---|---|---|
| conus | NAD27 to NAD83 | United States (USA) - lower 48 states including EEZ |
| alaska | Alaska to NAD83 | Alaska |
| hawaii | Old Hawaiian to NAD83 | Hawaii |
| prvi | Puerto Rico to NAD83 | Puerto Rico, Virgin Islands |
| stlrnc | St. Lawrence Island to NAD83 | St Lawrence: off the coast of Alaska |
| stpaul | St. Paul Island to NAD83 | St Paul: Pribiloff Islands off the coast of Alaska |
| stgeorge | St. George Island to NAD83 | St George: Pribiloff Islands off the coast of Alaska |
| HARN Readjustments | ||
| alhpgn | NAD83 to NAD83 (HARN) | Alabama |
| azhpgn | NAD83 to NAD83 (HARN) | Arizona |
| cahpgn | NAD83 to NAD83 (HARN) | California, south of 38 degrees North |
| cnhpgn | NAD83 to NAD83 (HARN) | California, north of 38 degrees North |
| cohpgn | NAD83 to NAD83 (HARN) | Colorado |
| emhpgn | NAD83 to NAD83 (HARN) | Idaho and Montana, east of 113 degrees West |
| ethpgn | NAD83 to NAD83 (HARN) | Texas, east of 100 degrees West |
| flhpgn | NAD83 to NAD83 (HARN) | Florida |
| gahpgn | NAD83 to NAD83 (HARN) | Georgia |
| kyhpgn | NAD83 to NAD83 (HARN) | Kentucky |
| lahpgn | NAD83 to NAD83 (HARN) | Louisiana |
| mdhpgn | NAD83 to NAD83 (HARN) | Maryland and Delaware |
| mehpgn | NAD83 to NAD83 (HARN) | Maine |
| mihpgn | NAD83 to NAD83 (HARN) | Michigan |
| mshpgn | NAD83 to NAD83 (HARN) | Mississippi |
| nbhpgn | NAD83 to NAD83 (HARN) | Nebraska |
| ndhpgn | NAD83 to NAD83 (HARN) | North Dakota |
| nehpgn | NAD83 to NAD83 (HARN) | New England (Connecticut, Massachusetts, New Hampshire, Rhode Island, and Vermont) |
| nmhpgn | NAD83 to NAD83 (HARN) | New Mexico |
| nyhpgn | NAD83 to NAD83 (HARN) | New York |
| okhpgn | NAD83 to NAD83 (HARN) | Oklahoma |
| pvhpgn | NAD83 to NAD83 (HARN) | Puerto Rico, Virgin Islands |
| sdhpgn | NAD83 to NAD83 (HARN) | South Dakota |
| tnhpgn | NAD83 to NAD83 (HARN) | Tennessee |
| vahpgn | NAD83 to NAD83 (HARN) | Virginia, excluding West Virginia |
| wihpgn | NAD83 to NAD83 (HARN) | Wisconsin |
| wmhpgn | NAD83 to NAD83 (HARN) | Idaho and Montana, west of 113 degrees West |
| wohpgn | NAD83 to NAD83 (HARN) | Washington and Oregon |
| wthpgn | NAD83 to NAD83 (HARN) | Texas, west of 100 degrees West |
| wyhpgn | NAD83 to NAD83 (HARN) | Wyoming |
For more information about NADCON grid data files, refer to the National Geodetic Survey web site.