Dots...and more dots

For Lab 9, aim for 1000 to 2000 total dots on the map (1500 works). Yes, that is a heck of a lot of dots. But this is the way to make a very nice distribution. Dot density maps are not hard to make, they just take time (and lots of patience).

How do you decide the value of your dot? It is a little guessing, a little sleuthing. First, I'd say that 1500 dots is a very, very rough guide for the total number on your entire map (not necessarily the case for other states). With that in mind, you could add up all the values in your data and divide it by 1500. The number you will get is your first guess. Next you need to make sure that your county with the smallest number of values will have a min of 1 dot (if it has data, it should really have a dot). If it has no data, then it can be blank). If your smallest value is, say 532, then aim to make your dot value 500 or lower.

Some comments about the sample map in the write-up:

1.The dot in the legend has a small box around it. I hate that box. Please don't but a box around it! Showing the dot in the legend is optional. If you feel it is so small it will get lost, leave it out.

2. In the example map, the ancillary idea was taken too far. I feel as if I'm looking at the major highways of WV -- too many lines of dots and clumps. This is the finesse part -- learning to scatter but let some clumps. Do aim to have the highest value location coalesce (and potentially a few more places depending on your data).

3. Yes, I emphasized "small" dots. But don't go too small. Again, try mapping the county with the highest number of values to gauge the density of the dots.

4. Keeping your basemap on a layer separate from the dots will help you resize dots if needed. And you can lock the basemap so it doesn't move. And you can more easily give it a tinted fill or fiddle with the boundary line thickness/tints.

5. If you find tricks or have questions, please post a comment here. Thanks!