how can I add MONTH+DAY to the X axis using ggplot2

[SquuooD]

Hi, i am learning R and im quite new in this field. I am trying to study SO2 values during time but I don't know how to combine MONTH+DAY in the same axis.
I am using this code

ggplot(data= "data") +
geom_point(mapping = aes(x=(MONTH=1)+DAY, y = SO2,colour=SO2,))

Then I will introduce title, etc..
***MONTH AND DAY are two colums in my data frame.

With month=1 I want to select January. There is a code to change the month number to the name? EX: 1=January, 2=February.. etc..

Thanks in advance! This community is great!

[technocrat]

See the FAQ: How to do a minimal reproducible example reprex for beginners. Here is an example based on an assumed dataset.

suppressPackageStartupMessages({
  library(ggplot2)
})
dat <- data.frame(x = 1:12,
  y = c(12,9,14,15,10,11,9,6,10,11,11,10))

p <- ggplot(dat,aes(x,y))
p + 
  geom_line() +
  scale_x_discrete(limits = 1:12, labels = month.abb) +
  labs(title = "Monthly Variation in SO2 levels at Station 1, 2017",
       caption ="Prepared by Alvaro Rodriguez Castrillo, 2020-05-21") +
  xlab("Month") +
  ylab("SO2 (ppm)") +
  theme_minimal()
#> Warning: Continuous limits supplied to discrete scale.
#> Did you mean `limits = factor(...)` or `scale_*_continuous()`?

[SquuooD]

Thanks for your quickly and good answer!

My question was more focus at the point of dividing de x axis in a daily axis. I mean separate January in 30 days (cause I have a dataframe with daily meassure). So my objective is to represent the same graph that I attach here with the column "DAYS" include.

Thanks in advance as always!

[technocrat]

Hence, the need for a reprex. See the FAQ: How to do a minimal reproducible example reprex for beginners.

[andresrcs]

Create a "date" class variable composed of your MONTH and DAY variables for plotting purposes, see this example with made-up data

library(tidyverse)
library(lubridate)
library(scales)

sample_df <- data.frame(
    month = rep(1:6, each = 30),
    day = rep(1:30, 6),
    so2 = rnorm(180)
)

sample_df %>% 
    mutate(date = ymd(paste("2021", month, day, sep = "-"))) %>% 
    drop_na() %>%
    ggplot(aes(x = date, y = so2)) +
    geom_point() +
    scale_x_date(date_breaks = "10 days",
                 labels = label_date_short(format = c(NA, "%B", "%d", "%H:%M")),
                 expand = c(0.005,0.005))
#> Warning: 2 failed to parse.

^{Created on 2021-05-17 by the reprex package (v2.0.0)}

If you need more specific help, please provide a proper REPRoducible EXample (reprex) illustrating your issue.

[SquuooD]

@andresrcs

sample_df <- data.frame(
    month = rep(1:6, each = 30),
    day = rep(1:30, 6),
    so2 = rnorm(180)

Thanks for your help! You're great and you are helping me a lot! I have one more question (sorry if I am being awkward.
How could I include data from another dataframe in the same graph? Just adding another geom_point?
I guess no cause I am working now with the new dataframe with the MONTH and DAY combined.

Here I show you how I addapted the code you gave me:

SO2combined2019 <- data.frame (
  month = rep(MES),
  day = rep(DIA),
  so2 = (GRANADA_NORTE_19$SO2)
)




SO2combined2019 %>%
  mutate(date = ymd(paste("2019", month, day, sep = "-"))) %>% 
  drop_na() %>%
  ggplot(aes(x = date, y = so2)) +
  geom_point(mapping = aes(color=so2)) + 
  scale_x_date(date_breaks = "10 days",
               labels = label_date_short(format = c(NA, "%B", "%d", "%H:%M")),
               expand = c(0.005,0.005))

month= rep(MES) --> is my variable MONTH in my dataframe as the same as DIA=day.

And in case I want to select only 4 months for example, is just to type this? :

SO2combined2019 <- data.frame (
  month = rep(MES=1:4),
  day = rep(DIA),
  so2 = (GRANADA_NORTE_19$SO2)
)

[andresrcs]

@SquuooD

SO2combined2019 <- data.frame (
  month = rep(MES),
  day = rep(DIA),
  so2 = (GRANADA_NORTE_19$SO2)
)

I don't think this is the best way to go about your problem, I used that code just for creating sample data to use with my reproducible example, please read the guide on the link I gave you so you can understand this concept and try to better explain your problem.

There is also a Spanish version if you prefer

Pregunta Frecuente: ¿Cómo hacer un ejemplo mínimo reproducible (reprex)? - para principiantes

Un ejemplo mínimo reproducible consiste de los siguientes puntos: Un conjunto de datos mínimo que permita reproducir el problema. El mínimo código ejecutable necesario para reproducir el problema, que pueda ser ejecutado con el conjunto de datos brindado y que incluya la información necesaria sobre los paquetes utilizados. Vayamos rápidamente sobre cada uno de estos puntos con ejemplos: Conjunto de Datos Mínimo (Datos de Muestra) Usted necesita proporcionar un conjunto de datos que sea lo suficientemente pequeño para ser pegado (razonablemente) en una publicación, pero lo suficientemente grande para reproducir el problema. Digamos, a manera de ejemplo, que usted está trabajando con el…