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diff --git a/man/sipoo.Rd b/man/sipoo.Rd
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--- a/man/sipoo.Rd
+++ b/man/sipoo.Rd
@@ -1,32 +1,39 @@
 \name{sipoo}
 \alias{sipoo}
+\alias{sipoo.map}
 \docType{data}
-\title{ Birds in the Archipelago of Sipoo (Sibbo)}
+\title{ Birds in the Archipelago of Sipoo (Sibbo and Borgå)}
 \description{
 Land birds on islands covered by 
-coniferous forest in the Sipoo archipelago, southern Finland (landbridge/
-oceanic distinction unclear from source). 
+coniferous forest in the Sipoo Archipelago, southern Finland.
 }
-\usage{data(sipoo)}
+\usage{
+  data(sipoo)
+  data(sipoo.map)
+}
+
 \format{
-  A data frame with 18 sites and 50 species (Simberloff & Martin, 1991,
-  Appendix 3). The species are referred by 4+4 letter abbreviation of
-  their Latin names (but using five letters in two species names to make
-  these unique). The example gives the areas of the studies islands in
-  hectares. 
+  The \code{sipoo} data frame contains data of occurrences of 50 land
+  bird species on 18 islands in the Sipoo Archipelago (Simberloff &
+  Martin, 1991, Appendix 3). The species are referred by 4+4 letter
+  abbreviation of their Latin names (but using five letters in two
+  species names to make these unique).
+
+  The \code{sipoo.map} data contains the geographic coordinates of the
+  islands in the ETRS89-TM35FIN coordinate system (EPSG:3067) and the
+  areas of islands in hectares.
 }
 
 \source{
-Simberloff, D. & Martin, J.-L.  (1991). 
-Nestedness of insular avifaunas:
-simple summary statistics masking
-complex species patterns.  \emph{Ornis
-Fennica} 68:178--192. 
+  Simberloff, D. & Martin, J.-L.  (1991).  Nestedness of insular
+  avifaunas: simple summary statistics masking complex species patterns.
+  \emph{Ornis Fennica} 68:178--192.
 }
+
 \examples{
 data(sipoo)
-## Areas of the islands in hectares
-sipoo.area <-  c(1.1, 2.1, 2.2, 3.1, 3.5, 5.8, 6, 6.1, 6.5, 11.4, 13,
-14.5, 16.1 ,17.5, 28.7, 40.5, 104.5, 233) 
+data(sipoo.map)
+plot(N ~ E, data=sipoo.map, asp = 1)
 }
+
 \keyword{datasets}