Map symbols for roads and road related features on Latvian topographic maps of the 1920s and earlier. From the book
Apzimejumi Merniecibas un Kulturtechniskiem Planiem
(Legends from Surveying and Cultural-Technical Plans)
Ministry of Agriculture
Riga, Latvia, 1928.
Original plate with translation to English below:
Public Roads:
1) a, b – carriageway edge
2) carriageway:
c – stone or macadamized, d – wood, e – gravel, f – unbuilt
3) g – culverts
4) h – stone bridge
5) i – rail bridge
6) k – road shoulder
7) l – ditches
8) m – greenery / vegetation
a – entrenchment
b – embankment
c – slope to one side
d – marsh dams
e – ditches
Winter road
Trail
Private roads
1) a, b – outer edge
2) carrageway:
c – unbuilt, d – stone or macadamized, e – wood, f – gravel;
3) g – culverts
4) h – wooden bridge
5) i – ditch
•••••••••••••••••••••••••••••••••••••
A scarce booklet of map symbols that appears in only one library (Berlin State Library) according to the global library catalog WorldCat. I will post more symbols from this booklet in the near future, as well as a PDF of the entire booklet.
Making Maps: DIY Cartography 
Very Interesting. A PDF of the booklet would be exellent.
Where can one find this publication?
The WorldCat resource lists only one copy in one library worldwide (in Berlin) as noted in the posting, thus it is quite rare. I bought my copy from a dealer in Estonia. I am working on getting the entire booklet scanned and formatted into a PDF and will post that in the near future (after a few more posts of particular plates). As for another actual copy, you can try book dealers in Europe who specialize in Latvian books.