+shorbird Posted March 4, 2010 Share Posted March 4, 2010 I recently recovered an unusual combination of related benchmarks--a triangulation station, 2 Reference Marks, and an azimuth mark, all set in different years. The triangulation station, TR0593, is a USC&GS disk set in 1955. Reference Mark 1, TR0594, is a USC&GS disk set in 1931. Reference Mark 2, TR1726, is a metal plate screwed to a concrete post set by the US Engineers in 1923. The azimuth mark, TR1741, is a NGS disk set in 1977. Usually, all four related marks are set at the same time by the same agency. In this case, the reference marks were set by two different agencies at two different times and neither mark was originally designated as a reference mark. The azimuth mark is a replacement for an earlier azimuth mark. Has anyone else found such an unusual combination? Quote Link to comment
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