My question is where can I get approximate position of the known black holes in our Galaxy (Milky Way) as Galactic coordinate system or maybe some other galaxy coordinates?
Gal coord. (ep=J2000) : 209.9563 -06.5399 [ 100 12 0 ]
where 209.9563 is a Galactic longitude, which changes from 0 to 360 degrees. -06.5399 is Galactic latitude, which is always around zero (+/- 10 degrees), because our galaxy is almost flat. Good explanation for galactic coordinates is on this wikipedia page.
To put the object on 2D map like this only Galactic longitude and distance to the object is needed. For example, this is the map of all black holes which I could find in wikipedia in our Galaxy.