Do you already have x/y coordinates in your CSV? If so, you should be able to use them directly in Tableau and drop them on the image of your floor map. Here is some information related to that process:
Hi Sarah, I dont have x/y in my CSV file originally. Once i annotate in Tableau I type down the x and y value based on Tableau scale on the CSV file and I refresh the data sources ( Item Number is my primary key)
As far as I know, there isn't a way to directly export the annotation on your viz. You *could* open your TWB in a text editor and write a script to pull out the individual values for each annotation point that you make. When you open the TWB somewhere in the text you'll see a section with annotation and each point will have some detail along these lines that you could use the harvest the data...but unless you like scripting and pulling values out of XML files, I would suggest using a different tool to mark off the locations and get screen coordinates if you need to automate it. I often do this sort of thing for geographic data in an open-source GIS package (QGIS), but for coordinates that are local (e.g,. set bottom corner to 0,0) there are probably simpler tools available to just add an image, set the bottom corner to 0,0 and then read off coordinates for the points that you add.
Here is what the annotation text looks like in the TWB.... there are x and y coordinate values and the lat/lon values for each point that I marked off on a map.
<projection name='EPSG:3857' u='-95.228438980263149' v='42.82628523806892' />