looking up country names from lat long

Hello - here is what I am sure is a quick question from someone new to R in
spatial stats. I have a long list of lat long coordinates and I would like
to do a location country check to extrapolate a country name from each
lat/long point.

so, for example, my data look like

lat, long
14.42, -89.92
14.42, -89.75
14.42, -89.58
14.42, -89.42
14.42, -89.25

continued for the terrestrial surface of the earth.

If I want to add country names, so I can use those names as tags to merge in
other data, is there an easy lookup that will allow me to do that, so I end
up with:

lat, long, country
14.42, -89.92, Guatemala
14.42, -89.75, Guatemala
14.42, -89.58, Guatemala
14.42, -89.42, El Salvador
14.42, -89.25, Honduras

GNcountryCode(lat=14.24,lng=-89.92)

On Mon, Dec 6, 2010 at 1:41 PM, Josh Tewksbury<tewksjj at gmail.com>  wrote:

Hello - here is what I am sure is a quick question from someone new to R in
spatial stats. I have a long list of lat long coordinates and I would like
to do a location country check to extrapolate a country name from each
lat/long point.

so, for example, my data look like

lat, long
14.42, -89.92
14.42, -89.75
14.42, -89.58
14.42, -89.42
14.42, -89.25

continued for the terrestrial surface of the earth.

If I want to add country names, so I can use those names as tags to merge in
other data, is there an easy lookup that will allow me to do that, so I end
up with:

lat, long, country
14.42, -89.92, Guatemala
14.42, -89.75, Guatemala
14.42, -89.58, Guatemala
14.42, -89.42, El Salvador
14.42, -89.25, Honduras

  My 'geonames' package (on CRAN) can do lookups via the geonames.org
web service:

GNcountryCode(lat=14.24,lng=-89.92)

$distance
[1] 0

$countryName
[1] "Guatemala"

$countryCode
[1] "GT"

  its being very slow at the moment though. You might have speedier responses.

  It can only look up one at a time, so you'll have to loop through
your data frame with the usual R loop/apply-type patterns.

Barry

An offline country map + overlay should work pretty fast.

##########
require(rgdal)
setwd(tempdir())
download.file("http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/110m/cultural/110m-admin-0-countries.zip",destfile
= "temp")
unzip(zipfile = "temp")
w = readOGR(tempdir(), '110m_admin_0_countries')
# some random points of interest
poi = SpatialPointsDataFrame(spsample(w, 10, "random"), data =
data.frame(id = 1:10))
poi at data$cntry =  w at data[overlay(poi, w), "NAME"]

plot(w)
plot(poi, add = T, col = 2)
text(poi, labels = poi$cntry, col = 2, cex = 1)
##########

Best wishes
Mihai

On 12/6/2010 3:19 PM, Barry Rowlingson wrote:

On Mon, Dec 6, 2010 at 1:41 PM, Josh Tewksbury<tewksjj at gmail.com>  wrote:

Hello - here is what I am sure is a quick question from someone new
to R in
spatial stats. I have a long list of lat long coordinates and I would
like
to do a location country check to extrapolate a country name from each
lat/long point.

so, for example, my data look like

lat, long
14.42, -89.92
14.42, -89.75
14.42, -89.58
14.42, -89.42
14.42, -89.25

continued for the terrestrial surface of the earth.

If I want to add country names, so I can use those names as tags to
merge in
other data, is there an easy lookup that will allow me to do that, so
I end
up with:

lat, long, country
14.42, -89.92, Guatemala
14.42, -89.75, Guatemala
14.42, -89.58, Guatemala
14.42, -89.42, El Salvador
14.42, -89.25, Honduras

  My 'geonames' package (on CRAN) can do lookups via the geonames.org
web service:

GNcountryCode(lat=14.24,lng=-89.92)

$distance
[1] 0

$countryName
[1] "Guatemala"

$countryCode
[1] "GT"

  its being very slow at the moment though. You might have speedier
responses.

  It can only look up one at a time, so you'll have to loop through
your data frame with the usual R loop/apply-type patterns.

Barry