A simple little diagram of the tram lines of the Société des Tramways de Constantinople, sometime in the 1920s (probably between 1923 and 1928, when trams began running on the Asian side of the city). While it’s a little hard to see because of the clumsy shading applied, the map is actually a decent trackage diagram – showing where the network is double-tracked or has terminus loops.
The colour combinations for each line shown in the legend were also used on the headboards of the trams themselves, and generally indicated which termini the trams ran between – an aid to illiterate riders.
See also: this roughly contemporaneous diagram of the lines on a ticket (July 2013, 5 stars).
Source: Wikimedia Commons
Your tramway map shows the routes traveled by the tramway to be on the west side of the Bosphorus Strait. This puts tramway routes in Europe, not Asia. Also, the name of the city was changed from Constantinople to Istanbul. Parts of the city lie on both sides of the Strait.
Paul, the “Asia” reference above is only an attempt at dating the map: I’m saying that the map has to be from before 1928, as there are no tramlines on the Asian side of the Bosphorus yet. As for the city name, there’s a song about that… but the fact is that the transit company still used “Constantinople” in its name at this point in time.