[R-sig-Geo] Combining polygons from a SpatialPolygonsDataFrame object

[O'Hanlon, Simon J]

Hi Jesús,
Check out maptools::unionSpatialPolygons. This function takes a spatial polygons object and aggregates polygons according to a vector ID which tell the function what input polygons belong to which output polygons, in your case the province IDs.

Note you may need to set gpclibPermit() to allow use of the gpclib package if rgeos is not available on your system.

HTH,

Simon


--------------------------------
Simon O'Hanlon, BSc MSc
Department of Infectious Disease Epidemiology
Imperial College London
St. Mary's Hospital
London
W2 1PG
________________________________
From: r-sig-geo-bounces at r-project.org [r-sig-geo-bounces at r-project.org] on behalf of Alonso Nanclares, Jesús Alberto [jaalonson at indra.es]
Sent: 14 June 2012 08:45
To: r-sig-geo at r-project.org
Subject: [R-sig-Geo] Combining polygons from a SpatialPolygonsDataFrame object

Dear list,

I have a Shapefile representing the censal sections of Spain, and my interest is creating a KML file with only 52 polygons representing the different provinces of Spain. I shall use readOGR, and my problem comes when I have a SpatialPolygonsDataFrame object in R and I want to merge in only one polygon all the censal sections of every province. I have an attribute with the province ID defined in the same object, so it would only be aggregating the censal sections with the same province ID, but still I don’t know how to do it.

I shall be grateful for any help. My kind regards,

Jesús Alberto Alonso Nanclares
Consultor Junior
Centro de Competencias Business Analytics

Avda de Bruselas, 35
28108 Alcobendas (Madrid)
España

T +34 914 805 863
jaalonson at indra.es
www.indracompany.com<http://www.indracompany.com>

[indra]


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