2011

DescriptionFile
Grid Data Catalog file for transformations
between the RGF93 and NTF datums used
Rgf93ToNtf.gdc
within France. Default grid data file:
gr3df97a.txt. Default fallback datum: NTF-
G.
Grid Data Catalog file for computing the
modeled difference in orthometric height
Vertcon.gdc
between the North American Vertical
Datum of 1988 (NAVD 88) and the Nation-
al Geodetic Vertical Datum of 1929 (NGVD
29) for a given location specified by latit-
ude and longitude. Default grid data files:
VERTCONC.94, VERTCONE.94, and VERT-
CONW.94. Fallback datum definition is not
recommended.
A binary compiled file used for storing co-
ordinate system category definitions. Also
called a dictionary file.
Category.csd *
Coordinate systems dictionary file.Coordsys.csd *
Datums dictionary file.Datums.csd *
Ellipsoids dictionary file.Elipsoid.csd *
Multiple Regression Transformation binary
files that store the coefficients required for
.mrt files *
multiple regression analysis. The base name
of the file is the same as the key name of
the datum with which it is associated.
Grid data files used by Vertcon.gdc..94 files *
Data files for determining the geoid height
for any position in the United States. These
.geo files *
are in GEOID96 format and are used by
GeoidHeight.gdc.
Creating New Coordinate Systems | 115