More globe plots in R
Here are a few quick examples of plotting geographic points and great circle arcs on the earth’s surface with R.
This is just a first pass. I have omitted any textures or surface data with any real area to it so that the lines and points are highlighted. Regarding the points and lines themselves, no fancy colors, limited plotting elements; only up to about 20,000 great circle arcs. The semi-transparency of the lines is what really limited me for now in terms of adding more elements. Solid colors are not so bad though. I am using
rgl for this. It can become resource intensive very quickly. I am still sussing out more optimal code for large data. I tend to do heavy processing in computing environments where I cannot seem to effectively (or invisibly, ideally) use
rgl. I am for now stuck plotting to the screen on my pc which is not the ideal place to be crunching very large data sets.
The graphics in my previous post on plotting on the sphere were also made using
rgl but in a completely different manner. That involved texture mapping and these maps here involve direct plotting of lines and points. I can save an image of many semi-transparent lines plotted on a 2D map and then load that as a texture wrapped on a sphere, which consumes far fewer resources. However, a large number of lines will not wrap smoothly, or even line up where they are supposed to meet at the dateline, due to the finite edges in the spherical texture.