Shawn: Aaah the possibilities of scatter plots in Tableau are endless. Please tell us you did this last weekend and not over the New Year break. ; - ))
And now I return to the annually scheduled celebration of Mummer's Day in Philadelphia, Pa.
Whoa! TDT / blog post material for sure. =)
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I hope some day I will have the skills like you in Tableau... (working for it.. hopefully someday will achieve)
Okay Shawn, I downloaded the work book and have a few questions.
(And yes your exercise does have a useful application. At the very least teaching about some of the features of Tableau, and understand more about what it does under the hood.)
If anyone else downloads the .twbx file, I highly recommend that once it displays, you add add the x and y dimensions as quick filters, and change the filter to continuous. Then select a range of about 100 values for each, e.g. from 1 to 100 on the x dimension and the same for the y dimension. Reducing the number of marks displayed with will make it much faster and easier to work with the file. Otherwise, there are a ton of marks on each worksheet which take a while to render.
At first I thought you might be playing with the packed circles algorithm to get 3 dots of red, green and blue color at each point in the scatter plot. Kind of like your post about using bubbles inside a scatter plot.
1st: I finally figured out that hitting the Shift button + dragging a second dimension onto the color shelf ADDED the second dimension to the color shelf instead of REPLACING it. That's how you got a different color for each of the combinations of the values in the r, g. b dimensions. And that's how Tableau shows a color key that has a comma btwn each of the 3 dimensions. See image below.
If Control + dragging a dimension or measure copies them, then what's the Shift + Drag-Selected-Pill-feature called?
And why does it ADD a second, and 3d dimension to the color shelf instead of replacing it.?
By way of context. I was stumped for a while on how you got three separate dimensions onto one color shelf. I started by dragging the "r" dimension onto the color shelf and then dragging the "b" dimension onto it. It just replaced the first dimension with the second.
2d: I see that by changing the order of each of the dimensions in the color section of Marks card, the colors in the image change. Can you give a little explanation why? And did you play around with the order to optimize the final image.
3d: Could you achieve the same result by using the "combine" feature to effectively concatenate the 3 dimensions and select a comma as the delimiting character? If we could do it this way too, am I correct in thinking that your method might be a faster b/c the combine dimension feature creates all the combinations in the view or (152 to the 3d power) and then a color is assigned to each combo. And somehow the multiple dimension pills on the color box render faster than that method?
Hey Bruce I'm traveling today so I don't have time to give you a detailed answer. But here are a few notes:
- The way I put multiple pills on the color shelf is to ctrl-select each of the three pills, then drag them onto the shelf all at once
- Color order only changes the colors until you re-assign the palette, then you'll get the same colors back.
- I used the negative numbers so I could reverse the light/dark assignments without having to create a custom palette that went from dark to light (left to right).
- Use combine? I don't see why not. Don't know if it would be faster or slower.
When I get back I plan on converting all the r/g/b values to hex values and then creating a custom palette that I hope can be 'assigned' such that it automatically assigns the 'real' color values, and we end up with photo's actual colors. Theoretically this should work. But each image would have to have it's own specific color palette.
Anyway, glad you found this instructive.