Just a couple of physics notes: I wrote r as a scalar. This is the magnitude of the vector r.; The 1 over 4πε 0 is just a constant.; Electric potential is a scalar quantity, not a vector.

I'm trying to use ggplot2 stat_contour() to make salinity contours on a ggmap object. It is working, but I want the contour lines to have labels. Here is what I tried using direct.labels() with the ...

Hello, I have been trying to do some contour plot with some datasets. However, in some case the labels included 'undefined'. ... Contour plot labels issue - Max Contour/Z data value limited to 9772 ...