2011

■
To set up a new grid data file for France (page 109)
■
To set up a new grid data file for Australia or New Zealand (page 110)
■
To use the new high accuracy GDA94 datum (page 111)
■
To use version 2 of the Canadian National Transformation (page 112)
■
To use version 1 of the Canadian National Transformation (page 113)
■
To modify a coordinate system definition file (page 116)
Overview of Grid Data Files and Datum Shift Issues
When converting between certain coordinate systems in North America,
France, Australia, and New Zealand, AutoCAD Map 3D uses grid-based data
files called grid data files to obtain
datum (page 2059) shift information.
For the United States, France, Australia, and New Zealand geography, the grid
data files are in the public domain and are distributed with AutoCAD Map
3D. The grid data files which cover Canadian geography are not in the public
domain and must be obtained from the proper authorities in Canada.
AutoCAD Map 3D uses Grid Data Catalog (GDC) files to determine the order
in which grid data files are used in areas of overlap when converting from one
datum (page 2059) to another.
See also:
■
Creating New Coordinate Systems (page 89)
■ Datum Shift Issues for North American Users (page 112)
■ Grid Data Files for Australia and New Zealand (page 109)
■ Grid Data Files for the United States (page 105)
■ Coordinate System Files (page 113)
■ Australian Datum Transformation and Coordinate System Changes (page
110)
You can do the following with grid data files
See this topic...To do this...
Grid Data Catalog (GDC) Files (page 104)Set up a new grid data file
Grid Data Files for the United States (page
105)
Specify a new grid data file for the United
States
Creating New Coordinate Systems | 103