Merging shapefiles and csv

Hi,

I have used this proceeding:

spatial.data <- readOGR(?.)
stat.data <- read.csv(?.)
spatial.data at data=data.frame(stat.data)

This will merge your statistical data to your spatial data. Make sure 
you have the same order in both sides of your data.

Hope this help, greetings.

El 31/07/2014, a las 09:10, sam cruickshank <sam_l_cruickshank at hotmail.com> escribi?:

Hi,Thank you Lyndon and Rafael for your thoughts.  After the sp::merge comment I followed the code below, but again it failed at the write OGR bit, but this time with "Error in writeOGR(spatial.data, dsn = "C:/Users/Laptop/Documents/Rworkspace/Shape",  :   Creating Name field failed"
This could be because the "new_layer" command...does this have to be named anything in particular?  Does it have to match the file name etc.  Lyndon I'll try yours next but must admit it's confused me a little.

Joining New Data to an Existing sp Object
# use to read in some vector data
library(rgdal)

# read something in, rows are identified by a column called 'id'
spatial.data <- readOGR(...)

# read in some tabular data, rows are identified by a column called 'id'
new_table <- read.csv(...)

# 'join' the new data with merge()
# all.x=TRUE is used to ensure we have the same number of rows after the join
# in case that the new table has fewer
merged <- merge(x=spatial.data at data, y=new_table, by.x='id', by.y='id', all.x=TRUE)

# generate a vector that represents the original ordering of rows in the sp object
correct.ordering <- match(spatial.data at data$id, merged$id)

# overwrite the original dataframe with the new merged dataframe, in the correct order
spatial.data at data <- merged[correct.ordering, ]

# check the ordering of the merged data, with the original spatial data
cbind(spatial.data at data$id, merged$id[correct.ordering])
Correctly Write 'NA' Values to Shapefile [bug in writeOGR()]
# libraries we need
require(rgdal)
require(foreign)

# pass 1: write the shapefile
writeOGR(spatial.data, dsn='new_folder', driver='ESRI Shapefile', layer='new_layer')

# re-make the DBF:
write.dbf(spatial.data at data, file='new_folder/new_layer.dbf')

Date: Thu, 31 Jul 2014 15:19:01 +0200
From: rafael.wueest at gmail.com
To: r-sig-geo at r-project.org
Subject: Re: [R-sig-Geo] Merging shapefiles and csv

Hi there

have a look at

?sp::merge

Should do what you need.

HTH, Rafael

On 31/07/2014 15:14, Lyndon Estes wrote:

I am not sure about the mismatch issue, but I thinking merging the
data slot of spatialPolygonsDataFrame with a data frame produces
undesirable results.

I wrote a function a while back that does the merge in such a way that
the problems are avoided, and perhaps this might help.  I think there
are other, more recent, and undoubtedly better solutions (in fact I
recall seeing a very recent thread about this, but not sure where)
than this one that you could find.

joinAttributeTable <- function(x, y, xcol, ycol) {
# Merges data frame to SpatialPolygonsDataFrame, keeping the correct
order. Code from suggestions at:
# https://stat.ethz.ch/pipermail/r-sig-geo/2008-January/003064.html
# Args:
#   x: SpatialPolygonsDataFrame
#   y: Name of data.frame to merge
#   xcol: Merge column name
#   ycol: Merge column name
# Returns: Shapefile with merged attribute table

  x$sort_id <- 1:nrow(as(x, "data.frame"))  # Column containing
original row order for later sorting

  x.dat <- as(x, "data.frame")  # Create new data.frame object
  x.dat2 <- merge(x.dat, y, by.x = xcol, by.y = ycol)  # Merge
  x.dat2.ord <- x.dat2[order(x.dat2$sort_id), ]  # Reorder back to original
  x2 <- x[x$sort_id %in% x.dat2$sort_id, ]  # Make new set of
polygons, dropping those which aren't in merge
  x2.dat <- as(x2, "data.frame")  # Make update x2 into a data.frame
  row.names(x.dat2.ord) <- row.names(x2.dat)  # Reassign row.names
from original data.frame
  x2 at data <- x.dat2.ord  # Assign to shapefile the new data.frame
  return(x2)
}

Hope it helps.

Best, Lyndon


On Thu, Jul 31, 2014 at 8:32 AM, HallS <sam_l_cruickshank at hotmail.com> wrote:

Hi all,

I'm struggling to know how this will come across as my data is confidential.

Basically I have a shapefile (.shp) and a csv file while contain the same
regions (i.e.) a column which has the same information.  Using this link:
https://sites.google.com/site/eospansite/alobotips/spatial_r_tips/rshp_xls
I managed to get quite far but once I got to the writeOGR command, I get the
error
 Error in writeOGR(RSANHS, dsn = "C:/Users/Laptop/Documents/Rworkspace/",  :
  number of objects mismatch

shape1 at data <- merge(shape1 at data,csv,by.x="RSA",
+                           by.y="RSA", all.x=T, sort=F)

###Checking it
dim(shape at data)

[1] 1745    2

dim(shape1 at data)

[1] 1747    5

This shows a discrepancy in two rows between the original shapefile and the
new merged one.  When I looked at the merged file in full, there were a
number of NA rows at the bottom where there was no corresponding data to the
shapefile.  I tried shape1 at data <- na.exclude(shape1 at data) and with na.omit,
and this did reduce the number of rows to 1690, but the problem persists.

Sorry if this is a really unhelpful question, I'm not sure how to do it when
data is confidential.



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Rafael W?est
rafael.wueest at gmail.com
http://www.rowueest.net

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