形状重叠的颜色R

Question

是否有可能使两个透明的形状重叠，但只有一种颜色而不会使颜色变深。

include("connect.php");
$query = "SELECT subjectID FROM subject";
$result = mysqli_query($DBConnect, $query);
$data = "";
?>
<select name="subject">
<?php
while($rows =mysqli_fetch_array($result))
{   $subjectID = $rows['subjectID'];
     $data=$subjectID;
    echo " Subject: <option value='$subjectID'>$subjectID</option>";}?>
<?php
//config form
echo '<form action="generate.php" method="post">
    Subject:&nbsp;<option name="data">'.$data.'</option>&nbsp;
    <input type="submit" value="GENERATE"></form><hr/>';

[

Answer 1

您能只使用没有填充的点和shape = 1，这是只有边缘的空心点吗？

library(ggplot2)
library(maps)
#> Warning: package 'maps' was built under R version 3.5.1
scenario <- subset(map_data("state"), region %in% c(
  "arizona", "new mexico", "texas", "oklahoma",
  "kansas", "missouri", "louisiana", "arkansas", "colorado", "nebraska"
))
set.seed(12345)
locations <- data.frame(
  LONG = runif(10, -115, -90),
  LAT = runif(10, 25, 40)
)

ggplot(data = scenario) +
  geom_polygon(
    mapping = aes(x = long, y = lat, group = group),
    fill = "palegreen",
    color = "black"
    ) +
  coord_fixed(1.3) +
  geom_point(
    data = locations,
    mapping = aes(x = LONG, y = LAT),
    fill = NA,
    size = 64,
    shape = 1
    )

由reprex package（v0.2.0）于2018-08-03创建。