tidy_it: Tidy up an object with overlapping polygons

In chrisbrunsdon/caricRture: 'Sketchy' style maps with R

Description

Cut out overlaps in a SpatialPolygons or SpatialPolygonsDataFrame object

Usage

tidy_it(x)

Arguments

x	a SpatialPolygons or SpatialPolygonsDataFrame object

Value

a SpatialPolygons object with overlaps cut out

Examples

# Create an object with two overlapping polygons
"MULTIPOLYGON (((30 20, 45 40, 10 40, 30 20)))" %>% readWKT(id="George") -> george
"MULTIPOLYGON (((15 5, 40 10, 41 35, 10 20, 5 10, 15 5)))" %>% readWKT(id="Mildred") -> mildred
rbind(george,mildred) -> p1
c("George","Mildred") -> ID

# Create a color scheme based on IDs of polygons in p1
'olivedrab' %>% adjustcolor(alpha.f=0.5) -> olive 
'lemonchiffon' %>%  adjustcolor(alpha.f=0.5) -> lemon
c(George=olive,Mildred=lemon) -> cammo

# Useful for the demo
function(x) sapply(slot(x,'polygons'), function(y) slot(y,'ID')) -> get.IDs

par('mfrow') -> old.mf
par(mfrow=c(1,2))
p1 %>% plot(col=cammo[p1 %>% get.IDs]); 'Before' %>% title
p1 %>% tidy_it -> p1_tidy
p1_tidy %>% plot(col=cammo[p1_tidy %>% get.IDs]); 'After' %>% title
par(mfrow=old.mf)

chrisbrunsdon/caricRture documentation built on May 13, 2019, 6:52 p.m.