Plot by FIPS Code using Shapefiles

hi, after running each individual line of code above, check that the
object still has the expected number of records and unique county fips
codes.  it looks like length( shapes$GEOID ) == 3233 but nrow( merged_data
) == 3109.  the way for you to debug this is for you to go through line by
line after creating each new object  :)

i'm also not sure it's safe to work with gis objects as you're doing,
there are some well-documented examples of working with tiger files here
https://github.com/davidbrae/swmap



On Tue, May 5, 2015 at 11:00 AM, Shouro Dasgupta <shouro at gmail.com> wrote:

I am trying to plot data by FIPS code using county shapes files.

library(data.table)

library(rgdal)
library(colourschemes)
library(RColorBrewer)
library(maptools)
library(maps)
library(ggmap)

I have data by FIPS code which looks like this:

dput(head(max_change))
structure(list(FIPS = c("01001", "01003", "01005", "01007", "01009",
"01011"), pred_hist = c(5.68493780563595e-06, 5.87686839563543e-06,
5.68493780563595e-06, 5.84476370329784e-06, 5.89156133294344e-06,
5.68493780563595e-06), pred_sim = c(5.60128903156804e-06,
5.82369276823497e-06,
5.60128903156804e-06, 5.75205304048323e-06, 5.80322399836766e-06,
5.60128903156804e-06), change = c(-1.47141054005866, -0.904829303986895,
-1.47141054005866, -1.58621746782168, -1.49938750670105,

-1.47141054005866

)), .Names = c("FIPS", "pred_hist", "pred_sim", "change"), class =
c("data.table",
"data.frame"), row.names = c(NA, -6L), .internal.selfref = <pointer:
0x0000000000110788>)

 I add leading zeroes by:

max_change <- as.data.table(max_change)
max_change$FIPS <- sprintf("%05d",as.numeric(max_change$FIPS))

I downloaded shapefiles from here:
ftp://ftp2.census.gov/geo/tiger/TIGER2014/COUNTY/.

I obtain the FIPS codes from the shapefiles and order them using:

shapes_fips <- shapes$GEOID

shapes_fips <- as.data.table(shapes_fips)
setnames(shapes_fips, "shapes_fips", "FIPS")
shapes_fips <- shapes_fips[with(shapes_fips, order(FIPS)), ]
shapes_fips$FIPS <- as.character(shapes_fips$FIPS)

Then I merge the FIPS codes with my original dataset using:

merged_data <- merge(shapes_fips,max_change,by="FIPS",all.X=T, all.y=T)
merged_data <- as.data.table(merged_data)

Which looks like this:

structure(list(FIPS = c("01001", "01003", "01005", "01007", "01009",

"01011"), pred_hist = c(5.68493780563595e-06, 5.87686839563543e-06,
5.68493780563595e-06, 5.84476370329784e-06, 5.89156133294344e-06,
5.68493780563595e-06), pred_sim = c(5.60128903156804e-06,
5.82369276823497e-06,
5.60128903156804e-06, 5.75205304048323e-06, 5.80322399836766e-06,
5.60128903156804e-06), change = c(-1.47141054005866, -0.904829303986895,
-1.47141054005866, -1.58621746782168, -1.49938750670105,

-1.47141054005866

)), .Names = c("FIPS", "pred_hist", "pred_sim", "change"), sorted =
"FIPS", class = c("data.table",
"data.frame"), row.names = c(NA, -6L), .internal.selfref = <pointer:
0x0000000000110788>)

But when I try to merged data back to the SpatialPolygonsDataFrame called
shapes, I get the following error:

shapes$change <- merged_data$change

Error in `[[<-.data.frame`(`*tmp*`, name, value = c(-1.47141054005866,  :

  replacement has 3109 rows, data has 3233

 Apologies for the messy example, what am I doing wrong? Any help will be
greatly appreciated. Thank you!

Sincerely,

Shouro

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