Building an Import Template for the Canadian Geoid Model HT2_0 in TGO
(Source File: HT2_0.BYN)

1.	Start Grid Factory from the Utilities Menu in TGO, available when no project is open.
2.	When asked what Grid to open, choose Cancel.
3.	Choose File/Import Grids
4.	On the Import Grid window, choose New and then name the template “Canada Geoid HT2_0 Import Template.
5.	Answer the sequence of questions as follows:
•	Check here if the grid is based on the WGS84 ellipsoid.  Yes (check box)
•	Interpolation Method ?  Biquadratic
•	Select type of file to import ? Binary
•	Start Data, Left Margin, Right Margin ?  80 0 0
•	Length of data record ? 4
•	Check if there is missing data and what is the missing data value ?  Yes (check Box) and 9999000.
•	What do columns represent ?  Longitude
•	Enter Latitude of first entry in a column, Latitude of last entry in a  column, enter latitude grid interval ? 83 59 00N   41 01 00N    0 02 00
•	Enter Longitude of first entry in a row, enter longitude of last entry in a  row, enter longitude grid interval ? 141 59 00W   48 01 00W   0 02 00
•	What type of data is in the grid file?  Geoid Separations
•	Select Geoid Separation Data Type,  offset and multiplier.  4 byte Integer, 0, 1000.0


The HT2_0 Geoid BYN file can then be converted into a GGF format by choosing Utilities/Grid Factory/Files/Import Grids and choosing the Canada Geoid HT2_0 Import Template you have just create and  then selecting Import.  Select the HT2_0.byn file and specify a description such as Canada Geoid Model HT2_0 and specify the output directory to be C:\Program Files\Common Files\Trimble\Geodata.  The file ht2_0_geo.ggf will be created in the output directory you have specified.

The model must then be defined to TGO by choosing Utilities/Coordinate System Manager/Edit/ Add Geoid Model and specifying a name such as Canada Geoid  HT2_0 and selecting the file ht2_0_~1.ggf.  (this interface does not show the full  ht2_0_geo.ggf name)