如何在ggplot2中将geom_vline()和geom_hline()图例与其他图例分开

我正在尝试在R中创建一个ggplot2用于显示地下水保护标准的水平线以及显示建筑项目开始的垂直线的图.我已经为测量单位创建了图例,以及样本是否低于检测限.所有这些传说都出现在我想要的地方,但来自水平和垂直线的传说都覆盖在其他传说上.我尝试了多种使用方法show_guide,使用不同的数据帧来获取数据,override.aes = list()但似乎没有任何方法可以获得理想的结果.

这是数据的样子:

head(dmr_data)
    location_id sample_date analysis_result lt_measure default_unit           param_name
154        MWH1  2004-06-02          0.0150                    mg/L   Arsenic, dissolved
155        MWH1  2004-06-02          0.0850                    mg/L    Barium, dissolved
156        MWH1  2004-06-02          0.0002          <         mg/L Beryllium, dissolved
158        MWH1  2004-06-02          0.0005          <         mg/L   Cadmium, dissolved
162        MWH1  2004-06-02          0.0020          <         mg/L      Lead, dissolved
164        MWH1  2004-06-02          0.0010          <         mg/L  Thallium, dissolved
    DMR_limit  GWPS non_detect
154   0.01000 0.010          0
155   0.17340 2.000          0
156   0.00005 0.004          1
158   0.00100 0.005          1
162   0.00500 0.015          1
164   0.00060 0.002          1

以下是情节的代码:

 combo_plot <- function(df){ 

  limits = df

  shaded_dates <- data.frame(xmin = c(as.POSIXct("2004-06-01", format = "%Y-%m-%d"), 
                                  as.POSIXct("2013-10-01", format = "%Y-%m-%d")), 
                         xmax = c(as.POSIXct("2013-10-01", format="%Y-%m-%d"), 
                                  max(df$sample_date)),
                         ymin = c(-Inf, -Inf), 
                         ymax = c(Inf, Inf),
                         years = c("background", "compliance"))

  ggplot(data = df, aes(x = sample_date, y = analysis_result)) + 
    geom_point(data = df, aes(colour = default_unit, shape = factor(non_detect)), size = 4) + 
    geom_line(data = df, aes(colour = default_unit), size = 1) +
    facet_wrap(~ param_name, scale="free") + 

# Plot legends, labels, and titles
ggtitle(paste("Time Series Plots for Monitoring Well", 
              df$location_id[1], "\n", sep=" ")) + 
ylab("Analysis Result") +
xlab("Sample Date") + scale_x_datetime(labels = date_format("%Y")) +
theme(axis.text.x = element_text(angle = 90)) +
theme(plot.margin = unit(c(0.75, 0.75, 0.75, 0.75), "in")) + 
theme_bw() + 
scale_colour_discrete(name = "Units", guide = "legend") + 

# add rectangles for date ranges
geom_rect(data = shaded_dates, aes(xmin = xmin, ymin = ymin, xmax = xmax, 
                                   ymax = ymax, fill = years),
          alpha = 0.2, inherit.aes = FALSE) +
scale_fill_manual(values=c("blue","green")) +

# add horizontal lines for EPA MCL and Upper Prediction Limit
geom_hline(data = limits, aes(yintercept = GWPS, linetype = "GWPS"), show_guide = TRUE, size = 0.75) +
geom_hline(data = limits, aes(yintercept = DMR_limit, linetype = "DMR Limit"), show_guide = TRUE, size = 0.75) +

# create custom legend using guide
theme(axis.title.x = element_text(size = 15, vjust=-.2)) +
theme(axis.title.y = element_text(size = 15, vjust=0.3)) +
guides(colour = guide_legend("Units"), fill = guide_legend("Dates"),
       linetype = guide_legend("Limits")) +
scale_shape_manual(name = "Measure", labels = c("Non-Detect", "Detected"),
                   values = c("1" = 21, "0" = 4)) + 

# add vertical line to show start of "East Pushout" construction
geom_vline(xintercept = as.numeric(as.POSIXct("2008-08-01", format="%Y-%m-%d")),
           linetype="dotted", show_guide = T)

}

然后我用plyr它为所有井创建刻面图

d_ply(dmr_data, .(location_id), .progress = "text", failwith(NA, combo_plot), .print = TRUE)

这就是输出的样子. 任何帮助,将不胜感激!