ggplot2 draws two legends

Question

I have almost complete the following graph, but there is one problem with it.

The legend in the graph is drawn twice.

Here is the data:

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Answer 1

You have three aesthetics that are mapped to Variable: shape, colour, and linetype. Legends are collapsed together when they have the same title and labels. You have set the title to blank for colour and given it custom labels ("Significant Z-Score" and "Moran's I Z-Score"). You need to do that for linetype and shape as well to get them to collapse all together.

Change

scale_linetype_manual(values=c(1,3)) +

to

scale_linetype_manual(values=c(1,3), name="", labels=c("Signficant Z-Score",   "Moran's I Z-Score")) +

and add

scale_shape_discrete(name="", label=c("Signficant Z-Score", "Moran's I Z-Score")) +

(You can also get rid of the scale_fill_discrete because you don't actually use the fill aesthetic anywhere.)

This gives