Problem with aggregating UScensus2000 FL data

Hi Roger,

On Mon, Aug 1, 2011 at 2:38 PM, Roger Bivand <Roger.Bivand at nhh.no> wrote:

On Mon, 1 Aug 2011, Ista Zahn wrote:

Oops, I got the examples mixed up. The Alabama example works, the
Florida example does not. I also should have given the version info,
as this may well be version specific.

You also need to provide the link to the data file, and the code prior to
what you show. The function county() is not defined anywhere, consequently
the attribute fields are nothing like tract boundaries such as those on:

Sorry I wasn't clear. The data and the county function are in the
UScensus2000 packages. Let me try again. A complete example leading to
the error is

library(UScensus2000)

library(maptools)
data(countyfips)

tmp <- county(fips = gsub("^..", "",
countyfips$fips[countyfips$acronym == "fl"]), state = "fl", level =
"tract")
dat <- as.data.frame(tmp)
tmp.county <- unionSpatialPolygons(tmp, dat$county)

http://www.census.gov/geo/www/cob/tr2000.html

The lines do intersect (touch), and should not in a topologically correct
setting; the coordinates seem odd - what is the projection? Did you run
checkPolygonsHoles() first?

I would if I could figure out how to convert a SpatialPolygons object
to a Polygons object... I'm just getting started with sp.

Thanks,
Ista

Roger

R version 2.13.1 (2011-07-08)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=English_United States.1252
[2] LC_CTYPE=English_United States.1252
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United States.1252

attached base packages:
[1] grid ? ? ?stats ? ? graphics ?grDevices utils ? ? datasets ?methods
[8] base

other attached packages:
[1] rgeos_0.1-8 ? ? ? ? ? ? stringr_0.5 ? ? ? ? ? ? quadprog_1.5-4
[4] directlabels_1.3 ? ? ? ?UScensus2000_1.00 ? ? ? gpclib_1.5-1
[7] UScensus2000cdp_0.03 ? ?UScensus2000blkgrp_0.03 UScensus2000tract_0.03
[10] rgdal_0.7-1 ? ? ? ? ? ? maptools_0.8-9 ? ? ? ? ?lattice_0.19-30
[13] sp_0.9-84 ? ? ? ? ? ? ? foreign_0.8-45 ? ? ? ? ?ggplot2_0.8.9
[16] proto_0.3-9.2 ? ? ? ? ? reshape_0.8.4 ? ? ? ? ? plyr_1.5.2

loaded via a namespace (and not attached):
[1] digest_0.5.0 tools_2.13.1

On Mon, Aug 1, 2011 at 11:09 AM, Ista Zahn <izahn at psych.rochester.edu>
wrote:

Hi all,
I am trying to aggregate the UScensus data for Florida up to the zip
code level using unionSpatialPolygons from the maptools package. This
works for other states, but not for Florida:

## Works
tmp <- county(fips = gsub("^..", "",
countyfips$fips[countyfips$acronym == "fl"]), state = "fl", level =
"tract")
dat <- as.data.frame(tmp)
tmp.county <- unionSpatialPolygons(tmp, dat$county)

## Returns error
tmp <- county(fips = gsub("^..", "",
countyfips$fips[countyfips$acronym == "al"]), state = "al", level =
"tract")
dat <- as.data.frame(tmp)
tmp.county <- unionSpatialPolygons(tmp, dat$county)
Error in TopologyFunc(groupID(spgeom[ids[[i]]], id[ids[[i]]]),
names(ids)[i], ?:
?TopologyException: found non-noded intersection between LINESTRING
(-0.640183 0.433522, -0.678743 0.433456) and LINESTRING (-0.678743
0.433456, -0.677839 0.434367) at -0.678743 0.433456

Does anyone have a suggestion about how to do this?

Thanks!

Ista
--
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org

--
Roger Bivand
Department of Economics, NHH Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no