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How I use shapefiles in R with ggplot2 and RGDAL
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library(rgdal) # R wrapper around GDAL/OGR | |
library(ggplot2) # for general plotting | |
library(ggmaps) # for fortifying shapefiles | |
# First read in the shapefile, using the path to the shapefile and the shapefile name minus the | |
# extension as arguments | |
shapefile <- readOGR("path/to/shapefile/", "name_of_shapefile") | |
# Next the shapefile has to be converted to a dataframe for use in ggplot2 | |
shapefile_df <- fortify(shapefile) | |
# Now the shapefile can be plotted as either a geom_path or a geom_polygon. | |
# Paths handle clipping better. Polygons can be filled. | |
# You need the aesthetics long, lat, and group. | |
map <- ggplot() + | |
geom_path(data = shapefile_df, | |
aes(x = long, y = lat, group = group), | |
color = 'gray', fill = 'white', size = .2) | |
print(map) | |
# Using the ggplot2 function coord_map will make things look better and it will also let you change | |
# the projection. But sometimes with large shapefiles it makes everything blow up. | |
map_projected <- map + | |
coord_map() | |
print(map_projected) |
Hi. when using the converted shapefile the map appears distorted, how can I solve it?
They know how to color each province according to the prevalence of something, with plot me it was much easier. Thank you
Thanks a lot! fortify is the best
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is it possible to read from github directly? ie i have r script and shapefile/geodatabase all on github, how can i connect them?