rcanvec-package: Find, load, and plot Canadian vector basemap data

In paleolimbot/rcanvec: Access and Plot CanVec and CanVec+ Data for Rapid Basemap Creation in Canada

Description

Provides an interface to the National Topographic System (NTS), which is the way in which several a number of freely available Canadian datasets are available. CanVec and CanVec+ datasets, which include all data used to create Canadian topographic maps, are two such items that are useful in creating vector-based maps for locations across Canada.

Details

This package provides access to the CanVec/CanVec+ datasets via the canvec.download function. CanVec data is organized by National Topographic System number (e.g. 021H01), so the nts function is provided to look up NTS number by location (e.g. lat/lon), parsed text (e.g. "21h1"), or bounding box. Searching a bounding box using prettymapr::searchbbox based on human-readable location may be helpful.(e.g. prettymapr::searchbbox("wolfville ns")). Using the canvec.qplot function, this data can be plotted using default options for standard layers. Combining the searchbbox() and canvec.qplot functions, it is possible to make a vector-based map of any location in Canada with one incredible super simple line of code (data is downloaded automatically): canvec.qplot(bbox=searchbbox("wolfville ns")). For prettier maps, the canvec.export function exports shapefiles in a human-readable format (e.g. building_021H01.shp). If more refined plotting or manipulation is desired, further functions are available to manually load or obtain filenames of cached files. Files are downloaded to the working directory by default, although this location can be defined using the cachedir argument available to many functions.

Author(s)

Dewey Dunnington <[e-mail]>

References

CanVec+ Product Specifications, National Topographic System (NTS) Documentation

Examples

library(prettymapr)

#nts() function generates nts references based on lat, lon, or
#bounding coordinates
nts('21h')
nts('21h1')
nts('21h1', '21a16', '21A15')
nts(lat=45.2, lon=-64.32)
nts(lat=c(45.2, 46.2), lon=c(-64.32, -64.81))
nts(bbox=makebbox(45.125, -64.25, 44.875, -64.75))

#variant ntsstring() converts nts to string formats or takes the same
#arguments as nts() and returns a string vector instead.
ntsstring(c("021", "H", "01"))
ntsstring(bbox=makebbox(45.125, -64.25, 44.875, -64.75))

#bbox functions from {prettymapr} make it easy to manipulate bounding boxes
wolfville <- searchbbox("wolfville ns", source="google")
wolfvillezoomedout <- zoombbox(wolfville, 0.5)

#easy plotting with canvec.qplot()
canvec.qplot(bbox=searchbbox("wolfville ns", source="google"))

#download canvec or canvec+ data. 250k references use canvec+ (large amounts of data)
#and 50k references use canvec data (older but distributed in smaller chunks).
canvec.download(nts('21h1'))

#load data
buildings <- canvec.load(nts("21h1"), "building")
lakes <- canvec.load(nts("21h1"), "waterbody")
rivers <- canvec.load(nts('21h1'), "river")
roads <- canvec.load(nts('21h1'), "road")
contours <- canvec.load(nts('21h1'), "contour")

#plot data
sp::plot(lakes, col="lightblue", border="lightblue")
sp::plot(rivers, add=TRUE, col="lightblue")
sp::plot(buildings, add=TRUE, pch=".")

#zoomed in
sp::plot(lakes, col="lightblue", border="lightblue", 
     xlim=c(-64.4,-64.35), ylim=c(45.05,45.1))
sp::plot(contours, add=TRUE, col="brown", lwd=0.2)
sp::plot(rivers, add=TRUE, col="lightblue")
sp::plot(buildings, add=TRUE, pch=".")
sp::plot(roads, add=TRUE, lwd=0.5)


#equivalent syntax in canvec.qplot()
canvec.qplot(nts("21h1"), layers=c("waterbody", "contour", "river", "road"))
canvec.qplot(bbox=makebbox(45.1, -64.35, 45.05, -64.4), 
            layers=c("waterbody", "contour", "river", "building", "road"))

#method returns plot data argument so data does not need to be loaded each time. 
#this will not work when changing nts sheets.
plotdata <- canvec.qplot(nts("21h1"), layers=c("waterbody", "contour", "river"))
plotdata <- canvec.qplot(bbox=makebbox(45.1, -64.35, 45.05, -64.4), 
                          layers=c("waterbody", "contour", "river"),
                          data=plotdata)

#easy exporting with human readable names
canvec.export(nts("21h01"), "~/canvecdata", layers=c("road", "river"))

paleolimbot/rcanvec documentation built on May 24, 2019, 6:13 p.m.