Do you have data with X,Y coordinates, and you just want to plot them on a background image?
I've done something similar by telling Tableau my X,Y fields are lat/lon, show as map, then use the custom background map feature to load up an image. It's a bit of a hack, but worked great for my custom interactivity.
There may be other ways - this was several versions ago, and I haven't had a similar need anytime recently.
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This sounds like you want to generate the data itself based off the image. Annotate Point identifies the x,y coordinates of a point on a particular image, this is true, but also as you say, the annotation method is good for a small number of items but not so much for a large number of items. Unfortunately, this question is somewhat outside of the scope of Tableau on its own.
To make your life easier you'd probably need to leverage a little something extra, which would be general image processing techniques or possibly looking at some sort of source file and pulling coordinates from there. Consider asking yourself the following questions:
- Is there something unique about each individual point that would make identifying it easy? Something you can recognize, like the presence of a particular color, or some sort of unique shape, where the pattern or shape is consistent to the point a computer could identify it correctly?
- Is this image likely to change in the future, or is this a one time cost?
If you can answer yes to #1 and no to #2, you may be able to write or obtain an image processing program that scans for points of interest and marks those points. I've seen several MATLAB style questions designed to identify elements that fit a certain pattern and then filter to those elements, and I've done a very, very basic version of this question identifying a specific color using Python, an image library and a pixel-by-pixel scanning algorithm.
Sorry that I didn't have an more straightforward answer to your question.
By this, i am getting the X/Y co ordinates from the imported image and then using them to report data. we do not have X/Y data coming directly from our database, hence this effort.
Thanks for your reply. it was helpful.
When i researched, i found solutions related to image processing and pattern search but was checking if there is anything in tableau which i was missing.
Currently its a manual task for us to plot manually those points on image to gather X/Y positions and then use them to report the Hotel data.