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POR: creating a map of selected Canadian provinces and U.S. states
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copied!<p>I am attempting to create a map of selected Canadian provinces/territories and selected U.S. states. So far the nicest maps appear to be those generated with GADM data: <a href="http://www.gadm.org/" rel="nofollow noreferrer">http://www.gadm.org/</a> </p> <p>However, I have not been able to plot the U.S. and Canada on the same map or plot only selected provinces/territories and states. For example, I am interested in Alaska, Yukon, NWT, British Columbia, Alberta, and Montana among others.</p> <p>Also, the U.S. map appears to be split along the international dateline.</p> <p>Can someone please help me to:</p> <ol> <li>plot the aforementioned provinces/territories and states on a single map</li> <li>avoid having the U.S. split along the International dateline</li> <li>overlay a latitude-longitude grid</li> <li>select a specific projection, maybe the polyconic.</li> </ol> <p>Maybe spplot does not allow users to specify projections. I did not see an option to select a projection on the spplot help page. I know how to select projections with the map function in the maps package but those maps did not appear to look as nice and I could not plot the desired subset of provinces/territories and states with that function either.</p> <p>I do not know how to begin adding a latitude-longitude grid. However, Section 3.2 of the file 'sp.pdf' seems to address the topic.</p> <p>Below is the code I have come up with so far. I have loaded every map-related package I have stumbled upon and commented out GADM data except for provincial/territorial or state boundaries.</p> <p>Unfortunately, so far I have only managed to plot maps of Canada or the U.S.</p> <pre><code>library(maps) library(mapproj) library(mapdata) library(rgeos) library(maptools) library(sp) library(raster) library(rgdal) # can0<-getData('GADM', country="CAN", level=0) # Canada can1<-getData('GADM', country="CAN", level=1) # provinces # can2<-getData('GADM', country="CAN", level=2) # counties plot(can1) spplot(can1, "NAME_1") # colors the provinces and provides # a color-coded legend for them can1$NAME_1 # returns names of provinces/territories # us0 <- getData('GADM', country="USA", level=0) us1 <- getData('GADM', country="USA", level=1) # us2 <- getData('GADM', country="USA", level=2) plot(us1) # state boundaries split at # the dateline us1$NAME_1 # returns names of the states + DC spplot(us1, "ID_1") spplot(us1, "NAME_1") # color codes states and # provides their names # # Here attempting unsuccessfully to combine U.S. and Canada on one map. # Attempts at selecting given states or provinces have been unsuccessful. # plot(us1,can1) us.can1 <- rbind(us1,can1) </code></pre> <p>Thanks for any help. So far I have made no progress with Steps 2 - 4 above. Perhaps I am asking for too much. Perhaps I should simply switch to ArcGIS and try that software.</p> <p>I have read this StackOverflow post:</p> <p><a href="https://stackoverflow.com/questions/5757058/can-r-be-used-for-gis">Can R be used for GIS?</a></p> <p>EDIT</p> <p>I have now borrowed an electronic copy of 'Applied Spatial Data Analysis with R' Bevand et al. (2008) and downloaded (or located) associated R code and data from the book's website:</p> <p><a href="http://www.asdar-book.org/" rel="nofollow noreferrer">http://www.asdar-book.org/</a></p> <p>I also found some nice-looking GIS-related R code here:</p> <p><a href="https://sites.google.com/site/rodriguezsanchezf/news/usingrasagis" rel="nofollow noreferrer">https://sites.google.com/site/rodriguezsanchezf/news/usingrasagis</a></p> <p>If and when I learn how to accomplish the desired objectives I will post solutions here. Although I may eventually move to ArcGIS if I cannot accomplish the objectives in R.</p>

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