How not to display levels without values using scale_fill_manual?

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This is the data.frame for behavior playback:

structure(list(CAATINGA = structure(c(2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 4L, 2L, 2L, 2L, 2L, 2L, 4L, 4L, 4L, 2L, 
2L, 2L, 4L, 4L, 4L, 2L, 2L, 4L, 4L, 4L, 4L, 4L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 4L, 4L, 4L, 4L, 2L, 2L, 2L, 2L, 2L, 2L, 
4L, 4L, 2L, 2L, 2L, 2L, 2L, 2L, 4L, 4L, 4L, 4L, 2L, 2L), .Label = c("3", 
"4", "15", "21", "25"), class = "factor"), x = c(-37.9473978000952, 
-37.94712830551, -37.9468588109248, -37.9465893163395, -37.9463198217543, 
-37.9468588109248, -37.9465893163395, -37.9463198217543, -37.946050327169, 
-37.94712830551, -37.9468588109248, -37.9465893163395, -37.9463198217543, 
-37.946050327169, -37.9473978000952, -37.94712830551, -37.9468588109248, 
-37.9465893163395, -37.9463198217543, -37.946050327169, -37.9457808325838, 
-37.9473978000952, -37.94712830551, -37.9468588109248, -37.9465893163395, 
-37.9463198217543, -37.946050327169, -37.9457808325838, -37.9476672946805, 
-37.9473978000952, -37.94712830551, -37.9468588109248, -37.9465893163395, 
-37.9463198217543, -37.9476672946805, -37.9473978000952, -37.94712830551, 
-37.9468588109248, -37.9465893163395, -37.9530571863852, -37.9527876918, 
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-37.9533266809705, -37.9530571863852, -37.9527876918, -37.9476672946805, 
-37.9473978000952, -37.953865670141, -37.9535961755557, -37.9533266809705, 
-37.9530571863852, -37.9527876918, -37.9525181972148, -37.953865670141, 
-37.9535961755557, -37.9533266809705, -37.9530571863852, -37.9527876918, 
-37.9541351647262, -37.953865670141, -37.9535961755557, -37.9533266809705, 
-37.9468588109248, -37.9465893163395, -37.9473978000952, -37.94712830551, 
-37.9468588109248, -37.9465893163395, -37.9463198217543, -37.9476672946805, 
-37.9473978000952, -37.94712830551, -37.9468588109248, -37.9465893163395, 
-37.9463198217543, -37.946050327169, -37.948206283851, -37.9479367892657, 
-37.94712830551, -37.9468588109248, -37.9465893163395, -37.9463198217543, 
-37.946050327169, -37.9457808325838, -37.9484757784362, -37.948206283851, 
-37.9476672946805, -37.9473978000952, -37.94712830551, -37.9468588109248, 
-37.9465893163395, -37.9463198217543, -37.946050327169, -37.9457808325838, 
-37.9487452730214, -37.9476672946805, -37.9473978000952), y = c(-7.72169360304366, 
-7.72196309762891, -7.72196309762891, -7.72196309762891, -7.72196309762891, 
-7.72223259221415, -7.72223259221415, -7.72223259221415, -7.72223259221415, 
-7.72250208679939, -7.72250208679939, -7.72250208679939, -7.72250208679939, 
-7.72250208679939, -7.72277158138464, -7.72277158138464, -7.72277158138464, 
-7.72277158138464, -7.72277158138464, -7.72277158138464, -7.72277158138464, 
-7.72304107596988, -7.72304107596988, -7.72304107596988, -7.72304107596988, 
-7.72304107596988, -7.72304107596988, -7.72304107596988, -7.72331057055512, 
-7.72331057055512, -7.72331057055512, -7.72331057055512, -7.72331057055512, 
-7.72331057055512, -7.72358006514037, -7.72358006514037, -7.72358006514037, 
-7.72358006514037, -7.72358006514037, -7.72384955972561, -7.72384955972561, 
-7.72384955972561, -7.72384955972561, -7.72384955972561, -7.72411905431085, 
-7.72411905431085, -7.72411905431085, -7.72411905431085, -7.72411905431085, 
-7.72411905431085, -7.72438854889609, -7.72438854889609, -7.72438854889609, 
-7.72438854889609, -7.72438854889609, -7.72438854889609, -7.72465804348134, 
-7.72465804348134, -7.72465804348134, -7.72465804348134, -7.72465804348134, 
-7.72492753806658, -7.72492753806658, -7.72492753806658, -7.72492753806658, 
-7.72573602182231, -7.72573602182231, -7.72600551640755, -7.72600551640755, 
-7.72600551640755, -7.72600551640755, -7.72600551640755, -7.7262750109928, 
-7.7262750109928, -7.7262750109928, -7.7262750109928, -7.7262750109928, 
-7.7262750109928, -7.7262750109928, -7.72654450557804, -7.72654450557804, 
-7.72654450557804, -7.72654450557804, -7.72654450557804, -7.72654450557804, 
-7.72654450557804, -7.72654450557804, -7.72681400016328, -7.72681400016328, 
-7.72681400016328, -7.72681400016328, -7.72681400016328, -7.72681400016328, 
-7.72681400016328, -7.72681400016328, -7.72681400016328, -7.72681400016328, 
-7.72708349474853, -7.72708349474853, -7.72708349474853), uso_car = c("RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
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"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
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"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", 
"RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp", "RESERVA_LEGAL.shp"
)), row.names = c(NA, 100L), class = "data.frame")

I am creating named Vectors for values and Labels when using Scale-fill_manual:

cols<- c(`3` = "black", `4` = "red", `25` = "blue", `67` = "pink", `69` = "green")

labels <- c(`3` = "A", `4` = "B", `25` = "C", `26` = "D")

The code stays that way:

ggplot() +  
  geom_raster(data=df_dummy, aes(x=x, y=y, fill=CAATINGA))+
  scale_fill_manual("Classes",labels = labels
                    ,values = cols, drop = TRUE)

inserir a descrição da imagem aqui

The classes 67 and 68 have no value in the Fill of the geom_raster I used in the CAATINGA column and are still appearing in the legend. How do I remove these values from the legend? I’m using drop = TRUE but the scale_fill_manual insists on showing levels without values.

r ggplot2

1 answer

2


Values that are not in the column CAATINGA appear in the caption because they are in the vector cols. And as only some of those values are also names vector labels, those who are not are in the legend with the names that they have in cols. Values common to both vectors are in the label with the expected values.

To solve the problem, the code below is used droplevels to create an array of levels present in the column CAATINGA. Afterward intersect to keep the values/names common to the three vectors, this now created, cols and labels. Following the match creates indexes to extract only the common values of cols and labels, to be used in scale_fill_manual.

Note that there is still the level "21", present in CAATINGA but not in the color vector or in the Labels vector. This data is grey.

library(ggplot2)

cols <- c(`3` = "black", `4` = "red", `25` = "blue", `67` = "pink", `69` = "green")
labels <- c(`3` = "A", `4` = "B", `25` = "C", `26` = "D")

fac <- droplevels(df_dummy$CAATINGA)
common <- intersect(names(cols), names(labels))
common <- intersect(common, levels(fac))
i_cols <- match(common, names(cols))
i_labels <- match(common, names(labels))

ggplot() + 
  geom_raster(data=df_dummy, aes(x=x, y=y, fill=CAATINGA))+
  scale_fill_manual("Classes",labels = labels[i_labels]
                    ,values = cols[i_cols], drop = TRUE)

inserir a descrição da imagem aqui

However, I believe that the best solution is to have cols and labels corresponding to the data. The names of these two vectors are the levels of CAATINGA.

cols2 <- c(`3` = "black", `4` = "red", `15` = "blue", `21` = "pink", `25` = "green")
labels2 <- c(`3` = "A", `4` = "B", `15` = "C", `21` = "D", `25` = "E")

ggplot() + 
  geom_raster(data=df_dummy, aes(x=x, y=y, fill=CAATINGA))+
  scale_fill_manual("Classes", labels = labels2
                    ,values = cols2
                    ,limits = force    # não chega só drop = TRUE
                    , drop = TRUE)

inserir a descrição da imagem aqui

  • Rui, this df is just a portion of a larger raster file. I need named vectors with all existing values and Labels because I need to plot in facets for each raster group, where levels will vary. ggplot already matches between the named vectors and the values of the variable used for fill. The secret was just to put limits = force in my code it has already worked as expected. I just didn’t understand the use of this argument. Could you explain? Obg.

  • @Artur_indio O force has to do with the Lazy Evaluation. Forces R to evaluate the arguments of scale_fill_manual and only then passes them, already evaluated, to the routine that plots the graph. See help("force").

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