Add NA value to ggplot legend for continuous data map

Question

I\'m using ggplot to map data values to a (fortified) SpatialPolygonsDataFrame, but many of the polygons have NA values because there is no data available.

I used na.va

Answer 1

you can replace your NAs with 0 using

data[is.na(data)] <- 0

that way your nas will be replaced by zero and yout legend will show "0s"

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