我做了如下图表：

代码如下：

heatmap_branquesCAT <- ggplot(varIPI_branques_CAT_long, aes(x = time, y = branques, fill=values)) +
  geom_tile(aes(width=31)) +
  geom_text(aes(label = round(values, 1)), family="serif", color="black", size=4) +
  scale_x_date(expand=c(0,0), breaks = "1 months", labels=date_format("%b %y")
               # limits = c(as.Date("2023/01/01"), NA)) +
              ) +
  scale_y_discrete(expand=c(0,0), labels=c("Subministrament d'aigua", "Indústries d'alimentació i begudes", "Altres indústries manufactureres", 
                                           "Materials i equips elèctrics, electrònics i òptics", "Energia elèctrica", 
                                           "Fabricació de productes farmacèutics", "Índex general (IPI)", "Indústries extractives",
                                           "Indústries manufactureres", "Fabricació de maquinària i equips mecànics", "Metal·lúrgia i fabricació de productes metàl·lics",
                                           "Fabricació d'altres productes minerals no metàl·lics", "Indústries del paper", "Fabricació productes cautxú i matèries plàstiques",
                                           "Indústries químiques", "Indústries tèxtils",
                                           "Fabricació de material de transport")) +
  labs(title = "Índex de Producció Industrial",
       subtitle = "% de variació interanual",
       x = "", 
       y = " ",
       caption = "Font: Idescat.") +
    scale_fill_gradient2(
      low = "#CC3300",
      mid = "white",
      high = "#66CC00",
   #   midpoint = 0, 
      limits = range(varIPI_branques_CAT_long$values)) +
  guides(color=guide_legend(title="")) +
  theme_minimal() +
  tema +
  theme(axis.text = element_text(size=12, colour = "black"), 
  legend.position="none") 

heatmap_branquesCAT

我的数据样本：

structure(list(time = structure(c(19083, 19113, 19144, 19174, 
19205, 19236, 19266, 19297, 19327, 19358, 19389, 19417, 19448, 
18993, 19024, 19052, 19083, 19113, 19144, 19174, 19205, 19236, 
19266, 19297, 19327, 19358, 19389, 19417, 19448, 18993, 19024
), class = "Date"), branques = c("Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries extractives", 
"Indústries extractives", "Indústries extractives", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"Indústries manufactureres", "Indústries manufactureres", "Indústries manufactureres", 
"alimentació", "alimentació"), values = c(-17.2, -12, 0.6, 
-6, 8.6, 7.5, 10, 37.1, 26.1, 28.3, 14, 16.8, -9.4, 0.8, 3.1, 
2.5, -2.7, 6.4, 1.9, -2.9, 1.5, 2.5, 0.1, -1.9, -0.1, 5.3, -1.7, 
1.8, -6.8, 4.6, 4.6), scaled_value = structure(c(-0.486164571662395, 
-0.269301398928164, 0.256174750389396, -0.0190746611578974, 0.589810400749752, 
0.543935498825203, 0.648196639562814, 1.77838740515852, 1.31963838591303, 
1.41138818976213, 0.815014464742992, 0.931786942369116, -0.160869812561049, 
0.0939546003127367, 0.338515461609155, 0.274716976053568, -0.278203232094857, 
0.689407132164886, 0.21091849049798, -0.299469393946719, 0.168386166794255, 
0.274716976053568, 0.019523033831218, -0.193138584687407, -0.00174312802064446, 
0.572443241979642, -0.171872422835544, 0.200285409572049, -0.714159550058037, 
0.59745871515621, 0.59745871515621), dim = c(31L, 1L))), row.names = 20:50, class = "data.frame")

所以问题是现在绿色是根据整体最大值（= 50，2）着色的。这个梯度应该根据每行的最大值和最小值来着色。