Is there a map of the galaxies?
I see that there are many maps of a single galaxy, the Milky Way, showing the positions of the stars within our galaxy.
I could not find a map of Galaxies, however. Is there such a map? In lieu of that I suppose I could make my own map if I knew celestial coordinates of all the nearby galaxies and the distances to those galaxies. Is there such a data table readily available?
A map of all galaxies gets kind of unwieldy, like a map of all stars in the milky way or a map of every house in the country, or every grain of sand on a beach . . . you get the idea.
Start here - Local Group
Then Virgo Supercluster
Then local superclusters
And an article, even if it's a summary it's very much worth reading, with a more recent map with a "ginormous" supercluster that includes the milky way.
The largest of these maps is some 520 million light years across, so this is just a tiny part of the entire known universe, which (depending on how you measure) is either 27.5 billion light years across or 84 billion light years across.
It's worth pointing out, I haven't actually answered your question, and that was deliberate, cause I think the nearest 520 million light years is enough and it's all we have a really good picture of anyway (as far as I know). The farther out you go the more holes and inaccuracies there will be in the map.
There's also some closer stuff that's blocked by the Milky way so we can't see it, like the great attractor. No worries about superclusters eating our galaxy one day because dark energy expansion keeps these super-clusters from merging most of the time. Andromeda will merge with the Milky way in about 4 billion years though but we're not expected to ever merge with the great attractor, even as it pulls our galaxy towards it, the distance between us is growing.
The Lick galaxy catalog produced by Shane & Wirtanen (1967), included about 1,000,000 galaxies above magnitude 19 in the northern hemisphere: https://ned.ipac.caltech.edu/level5/March12/Coil/Coil1.html Someone made the survey into a lovely map around 1979: http://faraday.physics.uiowa.edu/astro/8C10.80.htm Structure is readily apparent.
I have a fun little bit of info that if nothing else shows just how big the Milky Way is. I we define the diameter of the solar system as about 200 AU (100x Earth-sun orbit and about the distance to the heliopause) then the ratio of the diameter of the Milky Way to the solar system is about 3 x 10E7. If we take the diameter of the observable universe as about 100 billion LY, then it is only about 10E6 times the diameter of the Milky Way! If you made a hologram with the Milky Way a seeable one millimeter (pencil lead diam.), then the whole obs. universe would be a one kilometer sphere. Doable!
That map was produced by Jim Peebles in the early 1970's following his converting the high resolution Shane-Wirtanen galaxy counts to a digital format. Peebles told me that his daughters had undertaken to produce the poster version using a stipple brush to represent the local galaxy density - the dots making up the image are not the galaxies. The picture is used as the frontispiece of his book "Large Scale Structure of the Universe" where credit is given to "J.A. Peebles and P.J.E. Peebles". Shane and Wirtanen had produced low-res isoplethic maps that showed superclusters of galaxies.