In crazybilly/rmapcounties: RMapCounties

Rmapcounties is designed to make it easy to pull regions around a particular location. The main usage is to find a list of counties within a certain driving distance of a particular address, allowing you to then easily create a group of people to invite to an event at the address.

I wrote the package as part of my work at Millikin University's Alumni & Development Center. We use Banner Advancement which uses modified FIPS codes (eg. "IL123") to create what they call "georegions." As such, rmapscounties provides tools that work with these style of codes.

Getting Maps via getcountymaps()

The most important step, of course, is getting the county maps. getcountymaps() provides a function to get county boundaries from the US Census Bureau in a format that's easily mapped. To use it, just call the function and assign it to an object that you want to contain your map data:

usmap  <- getcountymaps()

By default, getcountymaps() downloads the data and unzips it in the ./data directory, creating it if need be. You can use the dest argument to change that directory.

# downloads the data and unzips it into C:/mapdirectory
usmap  <- getcountymaps(dest = 'C:/mapdirectory')

If you've already downloaded the data, you can use set local=T and point the filelocation argument at the unzipped directory where your .shp files live. Note that you're calling out the directory name rather than the file names.

# assumes you've already downloaded the data and unzipped it into the directory C:/mapdirectory/tiger
usmap  <- getcountymaps(filelocation = 'C:/mapdirectory/tiger', local = T)

Note that, by default, the continentalonly argument is set to TRUE, which strips out Alaska, Hawaii, and other outlying islands--this allows the map to zoom to the entire US by default. If you need the extracontinental data, set continentalonly = F.

Find Counties Within Driving Distance

Once you've downloaded the map data, you're ready to find counties within driving distance of your location. countieswithindrivingdistance() returns a list of counties and the metadata about them:

countiesAroundDecatur  <- countieswithindrivingdistance(centerlocation = '1184 W Main, Decatur IL', countymaps = usmap )

The function defaults to a 90 min driving time, but the drivingtime argument allows you to adjust that.

The returned value is usually a list of class("drivingdistance") with the following items:

- `nearbydf` a data frame of nearby counties and their distance to the centerlocation
- `mapdata` a SpaitalPolygonsDataFrame of the nearby counties appropriate for use in a leaflet map
- `hobsonslist` a character vector of the Banner-style FIPS codes, ready to paste into a Hobsons filter
- `map` A pre-generated leaflet map

However, if only one output type is specified using the output argument, that output is returned by itself without being wrapped in a list.

Map Region

Often, regions have already been created in Banner. If you want to map a region to see where it extends to, mapregion() allows you to do so. Pass it a data frame or the location of a csv with banner-style FIPS codes in a column named bannercode and it will return a leaflet map with the counties in the region shaded.

Drivable Counties vs. Regions

At times, you need to compare an existing georegion to a drivable region. drivablecountiesvsregion() provides the tools to do so. - The regiondf argument takes a region data frame or file location of a csv with Banner-style FIPS codes. - The drivingdistance argument takes either a numeric driving time (in minutes) or an object of class(drivingdistance), ie. a list generated via countieswithindrivingdistance(). Using the latter allows you to avoid geocoding the same addresses over and over.

The function returns a list with metadata: - nearbydf provides a data frame of the nearby, drivable counties and their distance to the center of the region. - mapdata is a SpaitalPolygonsDataFrame of the nearby counties appropriate for use in a leaflet map - outsidecountiesdf is a data frame of counties that arewithin driving range but outside the original region - map is a leaflet map showing what counties are in the region, and which are drivable, but outside the region.

Bannerizing FIPS Codes

To create a data frame of county FIPS codes, use makebannerizedfips().

fipscodes  <- makebannerizedfips()

This uses the data from tigris::fips_codes and adds two new columns, one with Banner-style codes and a GEOID, which is what the data from getcountymaps() uses.

This function is primarily used internally by other functions, but is exported in case you need to reference the data manually or for other uses.

crazybilly/rmapcounties documentation built on Jan. 4, 2024, 6:32 a.m.