Move all the polygon vertices
You need the sp package for making spatial polygons objects and the rgeos package for doing buffering: library(sp) # convert your `r1` into a SpatialPolygons object: p = SpatialPolygons(list(Polygons(list(Polygon(r1)),ID=1))) plot(p) library(rgeos) # use a negative buffer for inside buffers: bp = gBuffer(p, width=-30) plot(bp, add=TRUE) That should do it... Barry On Mon, Feb 9, 2015 at 5:09 PM, Alexandre Santos
<alexandresantosbr at yahoo.com.br> wrote:
Dear Members,
I created a polygon (c1) below with the vertices data in UTMand I would like to know, if there are any function to move all the vertice in 30 metersinside with the reduction of my polygon area?
#Polygon coordinates --------------------------------------------------------------x.coords1<-c(371299.9, 371266.4, 371205.6, 371111.8, 371047.6, 371018.2, 371014.0, 371009.3, 370983.1, 370919.7, 370853.6, 370785.6, 370748.8, 370711.8, 370687.8, 370696.4, 370785.9, 370885.5, 371035.8, 371148.1, 371205.2, 371231.7, 371236.5, 371240.3, 371285.8, 371326.5, 371397.2, 371417.1, 371432.9, 371445.0, 371455.7, 371466.4, 371476.6, 371502.6, 371536.0, 371550.0, 371546.8, 371528.3, 371470.0, 371393.3, 371299.9, 371299.9)
y.coords1<-c(8246589, 8246560, 8246508, 8246428, 8246373, 8246349, 8246348, 8246352, 8246385, 8246465, 8246551, 8246638, 8246685, 8246732, 8246764, 8246771, 8246846, 8246932, 8247062, 8247160, 8247209, 8247230, 8247224, 8247221, 8247160, 8247107, 8247016, 8246991, 8246967, 8246939, 8246914, 8246892, 8246875, 8246846, 8246821, 8246809, 8246802, 8246785, 8246735, 8246669, 8246589, 8246589)
# Create a polygont05<-unique(data.frame(x=rev(x.coords1),y=rev(y.coords1)))c1 = cbind (t05$x, t05$y)r1 = rbind (c1, c1[1, ]) # juntaplot(c1) ##Plot the polygonpolygon(c1)## Countour#
Thanks in advance,
Alexandre
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