Purpose
In North America elevations are given using either Sea Level Datum of 1929, also called the National Geodetic Vertical Datum of 1929 (NGVD 29) or the North American Vertical Datum of 1988 (NAVD 88). Confusion often occurs when a user sees an elevation value using the older datum. Some may assume the elevation is incorrect and in fact the reader might find reliable documentation based on the North American Vertical Datum of 1988 to support their assumption. This simple template will aid editors to document that the National Geodetic Vertical Datum of 1929 is being used.
Note that Wikipedia encourages the use of NAVD 88 and conversions between the two datum can be done using a tool provided by the National Geodetic Survey. The tool is named VERTCON and can be found here. If an elevation is converted to NAVD 88 a citation linking to the source of the original NGVD 29 elevation should be provided, as well as the method of conversion.
Usage
The elevation of [[Mount Whitney]] is {{convert|14505|ft}}{{NGVD29}} → The elevation of Mount Whitney is 14,495 feet (4,418 m) NGVD 29