Figure idea: visual variables

[Nowosad]

I have an idea for a figure explaining visual variables. It could be a grid with three columns and four rows:

• Columns - represent data types (1. symbols, 2. lines, 3. polygons)
• Rows - represent visual variables (1. categorical colors, 2. sequential colors, 3. shapes, 4. sizes)

Each example could be directly taken from a tmap plots' legends. For more details - visit the Visual Variables section in chapter 5. What do you think about it, @mtennekes ?

[mtennekes]

That's a great idea!

I thought about another column 4. rasters, but this is essentially the same as column 3. Those 3 or 4 should cover all bases.
As for the rows: I think they are complete. At least, if you regard width as size.

There will be a couple of empty table cells: 2.3, 3,3, and 3.4.

[Nowosad]

Awesome. Could you try to make it happen?

PS: For now, I decided to treat width as size (you can find how I explain that in the book), but I am open to discussion if you want to use width as a different category.

[mtennekes]

I will:-)

Yes, I agree that width is treated as size.

An interesting note is that the non-contiguous cartogram can be regarded as symbols rather than polygons, where the shape corresponds to feature (with a 1:1 mapping provided that no two features have a similar shape) and the size to a numeric data variable.

[mtennekes]

I've added the figure.

I had to do some tricks to get the legends wide enough. Probably, tmap could benefit from that as well.

Great progress on chapter 5, btw.

[Nowosad]

The figure is awesome - thanks @mtennekes

[Nowosad]

Hi @mtennekes - I totally forgot about rasters for this figure. Should we add them to the right side of the figure or just change the column name "Polygons" to "Polygons/Rasters"?