IGLD 85 Conversion

IGLD 85 HEIGHT CONVERSION

This utility will convert elevations between the North American Vertical Datum of 1988 (NAVD 88) and the International Great Lakes Datum of 1985 (IGLD 85).
The conversion between an NAVD 88 Helmert height and an IGLD 85 height is performed through an intermediary dynamic height
NAVD 88-->Dynamic Ht-->IGLD 85
IGLD 85-->Dynamic Ht-->NAVD 88
The dynamic height is computed using the NAVD 88 gravity model. For details see the dynamic height and NAVD 88 gravity items in the Geodetic ToolKit.
The conversion between the dynamic height and the IGLD 85 height requires the application of a hydraulic corrector. The hydraulic correctors for the 5 Great Lake regions are represented by grid files which are accessed by this program.
Both steps of the conversion require the specification of the latitude and longitude of the point. This position is used in the first step to interpolate in the NAVD 88 gravity model, and in the second step to interpolate in the appropriate hydraulic corrector grid surface.

Enter the Latitude and Longitude on the NAD 83 datum using the following permissable formats:

degrees and decimals (xx.xxxx)
degrees, minutes and decimals (xx xx.xxxx)
degrees, minutes, seconds and decimals (xx xx xx.xxxx)

The input elevation should be in meters and decimals.

Specify a file of coordinates and elevations to be converted:

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Enter North Latitude:	(example: 43.301)
Enter West Longitude:	(example: 77 37.6)
Enter Input Height:	(example: 123.45)
Enter Station Name:	(Optional)