How to Make Data-Driven Bubble Maps in Adobe Illustrator

alright so we are going to make a bubble
map of cities of California and a bubble
map is a map where instead of just
putting dots on different places of
importance instead you put circles and
the circles are sized according to the
magnitude of some variable so got a big
city has a big bubble got small city has
a small bubble you can also use this in
scatter plots but we're going to do it
in a map today because it's way more fun
so first thing you need is a map of
california this is just a normal SVG map
and i'm going to cheat a little bit
later on and i don't know where things
like LA or san diego are so by putting a
map underneath my SVG map I'm ordered
I'm able to reference it and when
drawing my circles so just something you
want to have later on and I'm going to
click the little toggle visibility here
in order to hide it and then we're going
to be good to go so in order to make a
bubble map the most important thing you
need is the ability to make bubbles so
we are going to use the ellipse tool if
this is the rectangle tool for you over
here what you need to do is click and
hold and then come up with the ellipse
here so there are two ways actually two
ways to make circles the first way is
clicking and dragging and the second way
is just clicking once and they each have
their own ups and downs let's say so if
i'm using the ellipse tool i can click
and I can drag and I'll make a circle
but is that a circle no it's not a
circle it's an ellipse we need to
heighten the Wits to be the same so what
you do is you have to hold down shift so
hold down the shift key as you are
clicking and dragging and it will lock
the height and the width to be the same
and you will come out with a wonderful
wonderful circle but maybe won't be in
the right place you'll note that as I
drag my circle out I'm starting from the
top left of the circle instead of maybe
the center of the circle so if i wanted
to make San Francisco here I would click
and I would drag
and then I would have to move that
circle to be back over to San Francisco
which seems like a bunch of crap so
there's another key so let's say shift
makes a circle and the other thing you
want to do is alt centers it so if I am
making San Francisco here I pull it out
first I say oh it's not a circle I hold
down shift it becomes a circle and then
I hold down alt and it starts it from
the point that i clicked right fun and
good if I want to put a city down here
hold down alt to make it centered hold
down shift in order to make it a circle
and life is good same thing goes for
just clicking once so clicking once is
good if you want to have a specific size
of the circle so when I click and I
dragged in theory I could look up a goat
info window and see how big my circle is
as I make it bigger and bigger but who
really wants to do that let's say you
know this one here is twenty four point
six nine four millimeters if I really
really wanted 25 whatever do instead is
I would just click once and it would
bring up this menu and I could just type
25 by 25 hit OK and it would show up
this does the same thing with the upper
left if you're not holding alt so let's
say a click San Francisco and I say 1 30
by 30 it would show up down to the
bottom right of San Francisco what I do
instead is I hold down alt i click san
francisco 30 30 BAM right on san
francisco everyone is happy all right so
now that we know how to make circles we
need to figure out how to make circles
that are related to numbers so let's say
we have two cities we have little city
and it has let's say 50 people in it and
then we have big city and big city has
100
on it so big city is twice as big as
little city now we are going to make a
circle for little city where you're
going to hold alts down we're going to
click we will say 50 by 50 we've got a
nice big circle there looking good
little city gonna move it over there
give us a little more space and then
we're going to make one for big city
which is going to be 100 by 100 right so
this big city over here big city we made
a hundred by a hundred little city we
made 50 by 50 now is big city does the
circle for big city seem to be twice as
big as the circle for little city no
it's absurd it's way bigger than the
circle for little city so what's going
on here all we did was double the
numbers that should have worked well the
thing is that the human brain looks at
nope the human brain judges size based
on area not on diameter so when you type
in a number when you click with the
ellipse tool you say width and height or
100 or with a knight or 20 or within
hydro 10 what you're saying is draw me a
circle with the diameter of 10 and the
diameter is the distance from this side
to this side so all the way across
usually people talk about radius which
is that little green line from the
center of the circle to the outside but
going all the way across that is
diameter but the thing is we need to
figure out how to type in we need
something that has a 50-person area or
100-person area need to figure out what
to type in in order to put in that
diameter for that so there's all kinds
of math that's involved in it but
basically anytime you are making circles
always use the square root of your data
point that's all in caps because it is
so important and always the truth so
what we're going to do is we're going to
say okay we have 50 people in little
city square root of that is seven more
or less so let us make a city that is
seven by seven that's little city and
now we're going to do 100 and of course
the square root of 100 is 10 so now
we're going to do ten by ten and if we
look at those circles they're not nearly
as big as the other ones but big cities
area is twice as big as little cities
area so it's a little bit more realistic
it's a little bit more what human beings
perceive so always always always we're
going to use the square root which means
that we are going to go into excel so
that's hopefully where you've kept all
of your data maybe use Google Docs
whatever you want to do so right now
this size let's think of this is
actually the area so we're going to cut
and paste this here we need to figure
out a diameter for that and we're going
to say square root so in order to have a
diameter of 4 million are in order to
have an area of 4 million in a diameter
of 2,000 in order to have an area of
27,000 you need diameter of 163 so let's
draw Los Angeles so Los Angeles is let's
get that text out of the way those notes
just so we remember Los Angeles is down
here and we're going to say okay let us
make we're going to hold down alt we're
going to click on Los Angeles and we're
going to say 2000 by 2000 and it is way
too big that's
we're going to work it's never going to
work right so the diameter that it wants
to give us is 2000 but we need to scale
that back down to be a number that makes
a little bit more sense so what I say
just that you do is get your lips tool
and draw however big you want LA to be
so la is the biggest city I want it to
look pretty big i say i'm going to go
this big that seems pretty good to me
hopefully it also seems pretty good to
you now what you need to do is find out
how big this circle is and over here we
have the info window it says it's about
77 width and height if you don't have
the info window open go to the window
menu and then go to info and click that
and then should show up if it already
has a checkbox next to it it's hiding
somewhere on your screen so what has to
happen is somehow we have to turn this
number of 2,000 so la wants to be two
thousand millimeters we want la to be
seventy seven millimeters instead and
what you do is all you do is divide so
so divide two thousand by 77 which is
not google chrome by 77 that is let's
say 26 and so what we're going to do is
every single time we need to take the
size of city once to be we're going to
say no you need to be 27 times smaller
AKA yeah we'll just go with 26 times
smaller so we're going to go to excel
and we're going to say this is the
diameter that wants to be desired
diameter and then we're going to say
actual diameter right here
we're going to do is we're going to do
we found our magic number here we
divided 2000 by 77 we divided the size
the diameter the le wants to be by the
size that we want it to be which is 77
26 times smaller so we're going to say
we're going to take this diameter we're
going to divide it by 26 and then we're
going to pull that down through all of
these and these are the actual diameters
that we're going to use for all of our
cities so la is going to be 77 san diego
is going to be 45 and a half San
Francisco 35 and a half and so on and so
forth so let's make the circles first
we're going to get rid of a lie actually
because if we made a mistake in
calculating we're going to want to see
that mistake come back again and maybe
it'll be way too big or maybe it'll be
way too small and it's just kind of a
way to check with yourself about it so
we're going to make a new layer by
clicking create new layer and we're
going to call this city bubbles as
that's what we're about to draw here in
our lips we're going to make sure to
hold down alt in order to Center it so
holding down alt we're going to click LA
it's going to ask us how big do you want
it to be we can just cut and paste this
number in here if we'd like so great le
is huge always the biggest thing we've
ever seen now we need to do san diego
where is san diego well San Diego is
actually hidden right now by the bubble
that we just drew so what we're going to
do is we're going to make the entire
layer of City bubbles a little bit more
transparent so we can see through it so
if you have City bubbles selected over
here you can go to the opacity menu up
top now let's drop that down to say 40
so now we can see oh look san diego
right there looking good we're going to
hold down alt we're going to click san
diego we're going to type in c 45.5 done
opacity 40 now see through that
what's the next one's San Francisco 35
and a half 35.5 35.5 pacity 40 Fresno
let's say let's go 28 Fresno 2828 strap
our passe down Sacramento 27 a 727 and
Eureka is a lonely 6.3 great so we'll
drop that down to 40 drop this down to
40 okay so one thing you can see is that
all of these circles here I'm going to
hide the background here you can see
that all of these circles kind of
overlap each other and it doesn't look
very good I'm gonna be honest with you
so the reason why this happened is
because I lied to you earlier so what I
said was I was going to set the opacity
of the entire layer to be forty percent
so they would all blend into everything
below so you could see the outline so
you could see the city so you can see
all that but what I did instead was I
set the opacity of every single one of
these circles to be 40 so then when two
circles go on top of each other that end
up adding to one another so we want to
get rid of that so the way to do that is
we're going to select every single
circle and we're going to change the
opacity all at once one hundred percent
wonderful except is not wonderful they
no longer have that weird overlap but
you can also no longer see the outline
of the state underneath so the way to
change that is to actually change the
opacity on the entire layer so if you go
to the right hand side of the layers
palette you can see these little
circles when you click these circles
that select something on the screen in
your artboard and what you can do is if
you pick the top one it selects the
entire layer and then you can say okay
forty percent opacity now it's the whole
layer has forty percent opacity not each
individual circle so now they all blend
together in a wonderful beautiful way
and that's it there you have your your
bubble map if you want it to you could
do something like you know change the
color of Sacramento to be something else
because it's the capital probably I want
to do that because it looks terrible
Isley yeah there you go