Network Graph and US Map in R - r

I created a network graph from data on flows between US states. For each vertex, I have the lat/long of the state.
I am hoping to recreate a network kind of graph that shows the edges, except that I set the location of each vertex to be their geographic position and have a state boundary map in the background.
I am using to igraph to create my network. There have been some cool mapping examples in ggplot2, so I am wondering if that is an option. I believe I have seen similar options using Pajek, but I am hoping to stay within R.
maps in ggplot2
Any ideas/insight would be appreciated.
Brock

You have multiple packages dealing with maps. The most easy is maps, which gives you the states map. You can plot the vertices over using the coordinates.
map("state")
points(longitute,latitude)
These plots can be manipulated and added to using the base tools, keeping in mind the x axis is the longitude and the y axis is the latitude. edges can be plotted using the segments() function.
In ggplot2 just use the map_data() function, which gives you the shape-data of the map, and the geom_polygon() to add it to the graph in whatever form you want. Again, you can add the vertices and edges using the coordinates with the appropriate ggplot2 function geom_point() and geom_segment(). The code you link at shows you how, or otherwise look at this for an example.
Next to that, you can take a look at the packages maptools, which offers more functionality and, mapproj, which allows for different projections of the same map. You can use these packages as well to calculate geographical distances in a coordinate system.
mapdata contains more databases, and covers basically the whole world. You can work with coordinates pretty nicely.

Related

Overlapping data contour on a map

I have gone through few tutorials and answers here in stackoverflow such as:
Overlap image plot on a Google Map background in R or
Plotting contours on an irregular grid or Geographical heat map of a custom property in R with ggmap or How to overlay global map on filled contour in R language or https://blog.dominodatalab.com/geographic-visualization-with-rs-ggmaps/
They either don't serve my purpose or consider the density of the data to create the image.
I am looking for a way to plot contour on a map of a certain data, and would expect the image to look something like this:
or something like this taken from https://dsparks.wordpress.com/2012/07/18/mapping-public-opinion-a-tutorial/:
I have a data here that gives a contour plot like this in plot_ly but i want this over the map given by latitudes and longitudes.
Please guide me on how this can be done. Any links to potential answers or codes would be helpful.
Ok I did some digging and figured that to plot the data -which in this case are point values randomly distributed across the Latitude and Longitude, one has to make it continuous instead of the discreetly distributed one. To do this I interpolated the data to fill in the gaps, this method is given in Plotting contours on an irregular grid and then take it from there. Now the interpolation here is done using a linear regression, one can use other methods such as IDW, Kriging, Nearest Neighbourhood etc for which R-packages are easily available. These methods are widely used in climatology and topographic analysis. To read more about interpolation methods see this paper.

Plot points on map R maps package

I have a dataset of all powerplants and I've got their locations down to the format the maps package in R likes c("arkansas,clay", "arkansas,conway", ...).
Some counties have more than one powerplant, and there are 7+ types of powerplants, so I'd like to plot them as points on a map and not just color the counties, as I can see the maps package mainly doing. Was thinking to jitter their position a bit. But I don't know how to go from state/county name to location, or plot straight up points in the maps package.
Does anyone have any suggestions?
So I couldn't figure out how to do it with the maps package, but with ggplot, it's almost trivial. The first few lines of this answer made it really easy to construct a plot I needed.
Plotting bar charts on map using ggplot2?
One trick I did use was to create R's version of a hastable from the map_data in ggplot2.
usaMap=maps_data("county")
usaMap$locCode=paste(usaMap$region,",",usaMap$subregion,sep="")
usaMap2 = usaMap[!duplicated(usaMap$locCode),]
row.names(usaMap2)=usaMap2$locCode
currentGen$long = usaMap2[currentGen$locCode,"long"]+rnorm(nrow(currentGen),0,.05)
currentGen$lat = usaMap2[currentGen$locCode,"lat"]+rnorm(nrow(currentGen),0,.05)
where currentGen is my powerplants data frame and the format of the region matches exactly the format of usaMap$locCode.

How to obtain koppen-geiger climate map for ggmap

I would like to use ggmap to plot several data points on top of a koppen-geiger climate map.
The kopper-geiger data and GIS/KMZ maps can be downloaded here:
http://koeppen-geiger.vu-wien.ac.at/present.htm
I've managed to have a code to plot the points on regular maps, obtained through the get_map function but I fail to use other maps such as koppen-geiger.
Any help will be appreaciated!
Your basic problem is that the map you are attmepting to use is an image file that is not georeferenced. So unless you want to go through the unnecessary and probably time consuming process of georeferencing this image yourself, you will be better taking an alternative approach. There are perhaps a few ways to do this. But, unless you have very few data points to overlay on the map which you can place manually using the lat-long grid of the image, then the least painful method will certainly be to redraw the map yourself using the shapefile.
This is not the right place to give you an introductory lesson on GIS, but the basic steps are to
Download shapefile (which is available at the same website as the image you linked)
Project map to desired coordinate system
Plot map, coloring by climate class
Color the ocean layer
Add labels, legend, and graticule, as desired
Overplot with your own climate data, and legend for these.
If you are unsure how to approach any of these steps, then take an introductory course on GIS, and search the Web for instructional materials. You may find this resource useful.
https://cran.r-project.org/doc/contrib/intro-spatial-rl.pdf

Spacing of map scatter plot elements

I have a dense scatter plot on a map (produced using Python, matplotlib, and basemap). Here is a part of the image:
I'd like to solve the overlap problem. I think the way to do this is to combine this simple lat/lon coordinate mapping with the technique I often see implemented in those "spring-loaded" network (social, not computer) graphs.
Is there a simple existing algorithm to auto-magically move these points so that they are not overlapping? If so, I can easily than add a small line from each point to its the correct lat/lon coordinate where it is currently located.
Note: Hexbin and heatmap is not a solution since the discrete values are important and should not be compromised.

Automatically aggregating points into clusters when zooming in on a map

I read ggmap's documentation and while the density/contour maps look cool, I was wondering whether someone has replicated this example. It creates clusters of points on geographic locations. I have many points to plot on the whole US map, so many that it hides other important information. I am using ggplot and maps to plot these maps. I would appreciate if someone has any examples of cluster plots as given in this example or this example

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