getCentroid | R Documentation |
This function takes a list of dataframes or a matrices containing x and y values, which define zones (polygons), and calculates their centroids.
getCentroid(data)
data |
A matrix or a dataframe with two columns, for x and y coordinates |
Most of the coordinates for the intersection labels in this package were calculated using the formula for a centroid of a non-self-intersecting closed polygon, approximated by 10 vertices.
A list with x and y coordinates, for each zone in the input list.
Centroid. (n.d.). In Wikipedia. Retrieved January 06, 2016, from https://en.wikipedia.org/wiki/Centroid
venn("0110") # centroid for the intersection "0110" in a 4 set diagram centroid <- getCentroid(getZones("0110"))[[1]] text(centroid[1], centroid[2], labels = "0110", cex = 0.85) # centroids for the two zones in the "E not A" zones venn(5) area <- getZones("0---1") # list of length 2 polygon(area[[1]], col="lightblue") polygon(area[[2]], col="lightblue") text(do.call("rbind", getCentroid(area)), labels = c("zone 1", "zone 2"), cex = 0.85)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.