`scatter` plots and marker colors -- change?

Specific Domains Visualization
1

I get this strange warning when using scatter under Julia v. 1.0.2:

julia> scatter(rand(10))
'c' argument looks like a single numeric RGB or RGBA sequence, which should be avoided as value-mapp
ing will have precedence in case its length matches with 'x' & 'y'.  Please use a 2-D array with a s
ingle row if you really want to specify the same RGB or RGBA value for all points.

What is this? I do often want to use the same color for all markers. The same warning pops up if I do:

julia> scatter(rand(10),rand(10), mc=fill(:red,1,10))

What is this? Didn’t I make the marker color dimension equal to the points in the scatter plot? Isn’t that what the warning asks for?

2

That’s not supposed to happen. Do you have some weird defaults set in your startup.jl file? What backend are you using?

3

I have no startup.jl file, as far as I know. I use Julia 1.0.2 on two different Windows 10, 64bit (updated) computers. I use PyPlot as backend. In one case, I used a freshly installed Juno on a Windows 10 Home machine; in the other case, I used IJulia on Windows 10 Pro.

On my job desktop: Plots v0.21.0, PyPlot v2.6.3.

I tried to use GR as backend on my home computer last night, but there was a problem with GR. I just tried with gr() backend on my work desktop, and with gr() I don’t get this error message. I do get the error message with pyplot() backend, though.

Sometimes I also get an error message about to versions of plots being installed. On my home computer, I at first had to type Plots.plot() to make it work.
Anyway, perhaps a problem with PyPlot?

4

Yes, this is a pyplot issue, I get it with pyplot too

5

Good to know. Weird, I just switched my main Julia activity from v. 0.6.4 to 1.0.2, and I haven’t seen that behavior in pyplot before.

6

OK… so there is an issue with pyplot in Julia v1.0.2.

There are also issues with gr… gr has no support of LaTeX in either xlabel, ylabel, or title – only in label.

UPDATE: gr seems to have problems with combination of text and LaTeX math. Asn an example:

plot!(xlabel=L"time $t$ [s]")

fails, where I have used gr and LaTeXString. Thus, pure math (LaTeX) seems to work in label, xlabel, ylabel, title, and pure text seems to work, but not the combination.

7

One more bug in gr…

using Plots; gr()
Eig=rand(20,2)
scatter(Eig[:,1],Eig[:,2],shape=:x,ms=5,ma=0.6,mc=:rainbow,mz=1:20,label="")

gives black (or: washed-out black?) and very big markers…

image
image1365×946 66.7 KB

while using the pyplot backend gives the expected result:
image
image1444×971 63.8 KB

With both gr and pyplot, I get the following strange warning:

┌ Warning: rainbow is found in more than one library: misc, colorcet. Choosing misc
└ @ PlotUtils C:\Users\<user_name>\.julia\packages\PlotUtils\GxT73\src\color_gradients.jl:40
8

If you find bugs it’d be helpful if you open them as issues on Plots.jl. It’s much easier to track than discourse posts

1 Like
9

OK. Will try to do that.