Dear List,
Could someone please help me, with a tiny question?
I have read in a shapefile with readShapePoly:
sr <- readShapePoly("study_region")
It just contains of one polygon.
As i would like to sample random locations inside i do:
> sr.pts <- sample.Polygon(sr, 60)
However, the function tells me, that there is no "area" slot in the
object:
Error in getPolygonAreaSlot(x) : no Slot of name "area" for this
object of class "SpatialPolygonsDataFrame".
But when looking at the object, there is a slot called "area" (see
below). Do i have to convert the sr object to another spatial object
which can better be handled by package sp functions (because it was
read in with a maptools function)? And by the way, why there is no
rgdal binary for mac on CRAN?
> sr
An object of class SpatialPolygonsDataFrame
Slot "data":
Id
0 0
Slot "polygons":
[[1]]
An object of class Polygons
Slot "Polygons":
[[1]]
An object of class Polygon
Slot "labpt":
[1] 4510732 6009121
Slot "area":
[1] 250264.9
Slot "hole":
[1] FALSE
Slot "ringDir":
[1] 1
Slot "coords":
[,1] [,2]
[1,] 4510328 6008870
[2,] 4510339 6008963
[3,] 4510347 6009007
[4,] 4510371 6009123
[5,] 4510386 6009155
[6,] 4510427 6009198
[7,] 4510456 6009218
[8,] 4510536 6009269
[9,] 4510590 6009324
[10,] 4510655 6009395
[11,] 4510704 6009380
[12,] 4510752 6009358
[13,] 4510899 6009300
[14,] 4511018 6009246
[15,] 4511127 6009077
[16,] 4511246 6009065
[17,] 4511343 6009053
[18,] 4511213 6008975
[19,] 4511176 6008970
[20,] 4511123 6008980
[21,] 4511077 6009002
[22,] 4511007 6009021
[23,] 4510939 6009028
[24,] 4510866 6009021
[25,] 4510790 6009007
[26,] 4510723 6008985
[27,] 4510643 6008953
[28,] 4510579 6008934
[29,] 4510510 6008921
[30,] 4510420 6008893
[31,] 4510328 6008870
Slot "plotOrder":
[1] 1
Slot "labpt":
[1] 4510732 6009121
Slot "ID":
[1] "0"
Slot "area":
[1] 250264.9
Slot "plotOrder":
[1] 1
Slot "bbox":
min max
r1 4510328 4511343
r2 6008870 6009395
Slot "proj4string":
CRS arguments: NA
Dr. Gerald Jurasinski
Landscape Ecology and Site Evaluation
Institute for Management of Rural Areas
Faculty of Agricultural and Environmental Sciences
University of Rostock
Justus-von-Liebig-Weg 6
18059 Rostock
Germany
[EMAIL PROTECTED]
http://www.auf.uni-rostock.de/loe
+49 381 4983225 (tel)
+49 381 4983222 (fax)
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