I visited Uzbekistan in 2019 and espied numerous height markers on some fantastic buildings. I wasn't really looking for them (honest) but they just jumped out at me at every mosque/madrassah. I saw markers in walls at Khiva, Bukhara and Samarkand. The survey marks had Russian text as expected, as the USSR had significant influence in Uzbekistan from the 19th Century until its independence in 1991.
A Russian translator has told me that the script on the markers is a truncated form of the word for ‘level’ followed by the abbreviation GUGK, which in Soviet days stood for the Main Administration for Geodesy and Cartography, which came under the USSR Council of Ministers (ie. Government), and which has now become the Russian Federal Agency for Geodesy and Cartography. The rest of the numbers are no doubt unique to each bench mark.
