Tengo un conjunto de datos que tiene algunas instancias donde para una ubicación dada en la misma fecha y hora el valor es diferente. Estoy tratando de crear un marco de datos de subconjunto que muestre estas instancias. Este es un ejemplo de lo que quiero decir:

He examinado preguntas similares sobre SO, pero parece que no puedo obtener lo que quiero. Sigo recibiendo instancias donde este no es el caso.

Aquí está el código que estoy usando:

dat1<-data_concern_join2%>%
 group_by(locid,stdate,sttime,charnam,valunit)%>%
  filter(n()>1) 

Data de muestra

structure(list(orgid = c("USGS-NJ", "USGS-NJ", "USGS-NJ", "USGS-NJ", 
"USGS-NJ", "USGS-NJ", "USGS-NJ", "USGS-NJ", "USGS-NJ", "USGS-NJ", 
"USGS-NJ", "USGS-NJ", "USGS-NJ", "USGS-NJ", "USGS-NJ"), locid = c("USGS-01396030", 
"USGS-01396030", "USGS-01389850", "USGS-01389850", "USGS-01391500", 
"USGS-01391500", "USGS-01391500", "USGS-01391500", "USGS-01393960", 
"USGS-01390610", "USGS-01391500", "USGS-01390610", "USGS-01391500", 
"USGS-01378760", "USGS-01378760"), stdate = structure(c(11359, 
11359, 11359, 11359, 16504, 16504, 16112, 16112, 11367, 13860, 
12401, 13860, 16325, 13006, 13006), class = "Date"), sttime = structure(c(34200, 
34200, 36000, 36000, 40500, 40500, 39600, 39600, 36000, 39600, 
32400, 39600, 38400, 36900, 36900), class = c("hms", "difftime"
), units = "secs"), charnam = c("Specific conductance", "Specific conductance", 
"Specific conductance", "Specific conductance", "Specific conductance", 
"Specific conductance", "Specific conductance", "Specific conductance", 
"Specific conductance", "Specific conductance", "Specific conductance", 
"Specific conductance", "Specific conductance", "Specific conductance", 
"Specific conductance"), val = c(7450, 7300, 3210, 3180, 1930, 
1920, 1740, 1650, 1480, 1390, 1380, 1330, 1300, 1280, 1270), 
    valunit = c("uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", 
    "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", 
    "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", 
    "uS/cm @25C"), swqs = c("FW2-NT", "FW2-NT", "FW2-NT", "FW2-NT", 
    "FW2-NT", "FW2-NT", "FW2-NT", "FW2-NT", "FW2-NT", "FW2-NT", 
    "FW2-NT", "FW2-NT", "FW2-NT", "FW2-NT", "FW2-NT"), WMA = c(7L, 
    7L, 4L, 4L, 4L, 4L, 4L, 4L, 7L, 4L, 4L, 4L, 4L, 6L, 6L), 
    year = c(2001L, 2001L, 2001L, 2001L, 2015L, 2015L, 2014L, 
    2014L, 2001L, 2007L, 2003L, 2007L, 2014L, 2005L, 2005L), 
    HUC14 = c("HUC02030104050090", "HUC02030104050090", "HUC02030103120050", 
    "HUC02030103120050", "HUC02030103140070", "HUC02030103140070", 
    "HUC02030103140070", "HUC02030103140070", "HUC02030104050010", 
    "HUC02030103140010", "HUC02030103140070", "HUC02030103140010", 
    "HUC02030103140070", "HUC02030103010040", "HUC02030103010040"
    )), .Names = c("orgid", "locid", "stdate", "sttime", "charnam", 
"val", "valunit", "swqs", "WMA", "year", "HUC14"), row.names = c(NA, 
-15L), class = c("grouped_df", "tbl_df", "tbl", "data.frame"), vars = c("locid", 
"stdate", "sttime", "charnam", "valunit"), drop = TRUE, indices = list(
    13:14, 2:3, c(9L, 11L), 10L, 6:7, 12L, 4:5, 8L, 0:1), group_sizes = c(2L, 
2L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), biggest_group_size = 2L, labels = structure(list(
    locid = c("USGS-01378760", "USGS-01389850", "USGS-01390610", 
    "USGS-01391500", "USGS-01391500", "USGS-01391500", "USGS-01391500", 
    "USGS-01393960", "USGS-01396030"), stdate = structure(c(13006, 
    11359, 13860, 12401, 16112, 16325, 16504, 11367, 11359), class = "Date"), 
    sttime = structure(c(36900, 36000, 39600, 32400, 39600, 38400, 
    40500, 36000, 34200), class = c("hms", "difftime"), units = "secs"), 
    charnam = c("Specific conductance", "Specific conductance", 
    "Specific conductance", "Specific conductance", "Specific conductance", 
    "Specific conductance", "Specific conductance", "Specific conductance", 
    "Specific conductance"), valunit = c("uS/cm @25C", "uS/cm @25C", 
    "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", "uS/cm @25C", 
    "uS/cm @25C", "uS/cm @25C")), row.names = c(NA, -9L), class = "data.frame", vars = c("locid", 
"stdate", "sttime", "charnam", "valunit"), drop = TRUE, .Names = c("locid", 
"stdate", "sttime", "charnam", "valunit")))