[R-sig-Geo] manipulate SpatialPolygons object

[T.O. Richardson]

Hi list,

I have a SpatialPolygons object, 'HR_polygons' which may be composed of 
several disjoint polygons. Thus
length(HR_polygons[[1]]@polygons) is often > 1.
I sum the area across all the disjoint polygons to get the total area; 
'blob_area'.

How should I accomplish the following?:
- Enlarge or shrink the HR_polygons object (scaling all of the disjoint 
areas by an identical factor) such that it's blob_area reaches a new value- 
either larger (magnify) or smaller (shrink) than the original.

In this way the shape of HR_polygons is preserved, but the coordinates 
defining its edges will change completely. If the original HR_polygons 
contains > 1 disjoint areas , a magnification could conceivably cause the 
disjoint areas to overlap- that is fine.


Thanks
Tom






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