在绘图表面上使用条件着色 [英] Use conditional coloring on a plotly surface

问题描述

我第一次通过 R 使用 plotly 并尝试从网格创建一个表面并根据计算为它着色.

例如，我想使用 data(volcano) 中的表面，如

图书馆(情节)plot_ly(z = ~volcano) %>% add_surface()

但不是基于 z 值(高度)的颜色，而是说我想根据离我家在 (20,60) 处的小台面上的距离来着色.

house_loc <- c(20,60,150) # (x,y,z) 我的房子dist_to_house <- Vectorize(function(x,y,z){sqrt(sum((c(x,y,z)-house_loc)^2))})

到目前为止我已经尝试过:

color_me <-function(x){colorRampPalette(c('tan','blue'))(24L)[findInterval(x,seq(0,1,length.out=25),all.inside=TRUE)]}图书馆(dplyr)图书馆(重塑2)火山%>%融化(varnames=c('y','x'),value.name='z')%>%变异( d = dist_to_house(x, y, z) ,d_rel = d/max(d),d_color = color_me(d_rel)) ->dfplot_ly(df,type='scatter3d',mode='none', # 没有标记，只是表面x=~x,y=~y,z=~z,表面轴=2，surfacecolor=~d_color) # 最后一个参数似乎不起作用

刚刚返回的:

预期的结果是将房屋区域的景观染成棕褐色，并在远离房屋的区域逐渐褪色为蓝色.

有点

I am using plotly via R for the first time and trying to create a surface from a grid and color it based on a calculation.

For example, I would like to use the surface from data(volcano), as in

library(plotly)
plot_ly(z = ~volcano) %>% add_surface()

But instead of color based on the z-value (altitude), let's just say I wanted to color based on distance from my house on the little mesa at (20,60) .

house_loc <- c(20,60,150) # (x,y,z) of my house
dist_to_house <- Vectorize(function(x,y,z){sqrt(sum( (c(x,y,z)-house_loc)^2 ))})

So far I have tried:

color_me <-function(x){
  colorRampPalette(c('tan','blue')
  )(24L)[findInterval(x,seq(0,1,length.out=25),
                      all.inside=TRUE)]
} 

library(dplyr)
library(reshape2)
volcano %>% 
     melt( varnames=c('y','x'),value.name='z' ) %>%
     mutate( d = dist_to_house(x, y, z) ,
             d_rel = d/max(d),
             d_color = color_me(d_rel) 
     ) -> df

plot_ly(df,
        type='scatter3d',
        mode='none', # no markers, just surface
        x=~x,
        y=~y,
        z=~z,
        surfaceaxis=2,
        surfacecolor=~d_color) # last argument seems not to work

Which just returns:

The desired result would color the landscape tan in the region of the house and gradually fade to blue in the regions far from the house.

Somewhat related question uses mesh3d code found elsewhere and doesn't explain how to calculate (i, j, k)

解决方案

Your code virtually has everything you need, just use a surface plot and use your distance array as the color.

library(plotly)
library(dplyr)
library(reshape2)

house_loc <- c(20,60,150)
dist_to_house <- Vectorize(function(x,y,z){sqrt(sum( (c(x,y,z)-house_loc)^2 ))})

volcano %>% 
  melt( varnames=c('y','x'),value.name='z' ) %>%
  mutate( d = dist_to_house(x, y, z) ,
          d_rel = d/max(d)
  ) -> df

color <- df$d_rel
dim(color) <- dim(volcano)

plot_ly(df,
        type='surface',
        z=volcano,
        surfacecolor=color,
        colors=c('tan','blue'))

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