ggplot2散点图和标签

Question

I am attempting produce a scatter plot using the ggplot2 library. My data frame (called scatterPlotData) is in this form:

115 2.3
120 1.6
.
.
.
132 4.3

(The ... signifies many other similar values). Essentially, a 2 column data frame. I also have labels to go along with each of those points. Firstly, I'm having trouble with the scatterplot itself. I'm using the following code:

p <- ggplot(scatterPlotData, aes("Distance (bp)", "Intensity"))
p + geom_point()

However, using the above code, I get the following plot:

Obviously, it's not a scatter plot. So, I'd be very helpful if someone could point out what I'm doing wrong.

Secondly, it's about the labels. I will have many datapoints which would have the risk of overlapping datapoints. How should I go about just putting on labels to each point using ggplot? Also, it states that I could use the directlabels package to get a good overlap free labelled scatterplot using different colors, however, I'm not sure how I would go about that with ggplot as I haven't found any documentations regarding the use of directlabels with ggplot .

Any help with either (or both) question(s) are greatly appreciated - thanks.

Answer 1

Lose the inverted commas, at the moment you're making a plot of the text value... Having looked again, you will have problems with the brackets in your variable name ( Distance (bp) ). Change that to something without the brackets, then make the ggplot call without the inverted commas:

#Assuming Distance (bp) is the first column
names(scatterPlotData)[1] <- "Distance"
p <- ggplot(scatterPlotData, aes(Distance, Intensity) + geom_point()

As for non-overlapping labels, this is a vexed issue with lots of discussion on SO - I think you'll not get great responses from such a vague question here.

Answer 2

First, it would be much more helpful if you provided a reproducible example the precisely described your data.

You should not be passing variable names in aes in quotes. I'm not sure where you got that from, there wouldn't be a single example of anyone doing that that I can think of (unless they were using aes_string which is specifically for that case).

However , it appears that you have an awkward variable name, ie Distance (bp) . This is non-standard and not recommended. Names should not have spaces in them. The best thing to do would be to rename that column to something sensible and then do something like:

p <- ggplot(scatterPlotData, aes(x = Distance_bp,y = Intensity))
p + geom_point()

If you do not rename the column, something like this might work:

p <- ggplot(scatterPlotData, aes(x = `Distance (bp)`,y = Intensity))
p + geom_point()

Note that those are backticks, not single quotes.

As for the overlapping data, I would recommend reading here and here .