Blue line is the Uriankhay (1914) border line (reconstructed using SRTM mission DEM) as upper Yenisey watershed area plus upper Us and Kantegir river valleys. Red line is the Tuva Autonomous Oblast boundary line reprojected and vectorized from the Soviet atlas (1954 issue) with boundaries as of 1953.
<a href="//commons.wikimedia.org/wiki/User:Bogomolov.PL" title="User:Bogomolov.PL">Bogomolov.PL</a>
2009-01-17
Soviet atlas (1954 issue) with boundaries as of 1953 by <a href="//commons.wikimedia.org/wiki/User:Bogomolov.PL" title="User:Bogomolov.PL">Bogomolov.PL</a>.