如何在r射线渲染器中添加多边形到三维地图中？

Question

我是地理空间数据的新手，我只是通过查看web上的几篇文章，设法将其绘制成一些小片段。

我试图在使用rayshader包构建的3D绘图上绘制多边形边界，但是面对plot，而在顶部显示多边形边界E 211。

使用的形状文件是2011_Dist.shp，可以从Shapefile Github链接下载。

我尝试过的代码：

library(tidyverse)
library(sf)
library(elevatr)
library(raster)
library(rayshader)
library(osmdata)

# read districts shape file
ind_distirct_shp <- sf::st_read("local path/2011_Dist.shp")
ind_distirct_shp

# filter State
delhi_district_shp <- ind_distirct_shp %>% 
                       sf::st_as_sf() %>% 
                       filter(ST_NM %in% c("NCT of Delhi"))

# this shows the polygon boundaries that I need on top of map
plot(delhi_district_shp)

​

​

# download elevation data for State Delhi
delhi_raster <- elevatr::get_elev_raster(delhi_district_shp, z = 10, clip = "location")

# convert to matrix
delhi_mat <- raster_to_matrix(delhi_raster)

# 3D plot using Rayshader
delhi_mat %>%
  
  height_shade(texture = grDevices::colorRampPalette(c("#9a133d","orange","red","purple"
                                                       ))(256)) %>%
  plot_3d(heightmap = delhi_mat, 
          windowsize = c(800,800), # c(800*wr,800*hr) 
          solid = FALSE, 
          zscale = 1,
          phi = 90, 
          zoom = .6, 
          theta = 0,
          shadowcolor = "grey50",  
          linewidth = 6,
          background = "white",
          solidlinecolor = "#013b39") 

​

​

问题：现在当我试图修改这个以添加polygon lines时，它不起作用。

polygon_layer = generate_polygon_overlay(delhi_district_shp, extent = extent(delhi_raster),
                                    heightmap = delhi_mat) # , palette="grey30"

polygon_layer

delhi_mat %>%
  
  height_shade(texture = grDevices::colorRampPalette(c("#9a133d","orange","red","purple"
                                                       ))(256)) %>% 
  add_overlay(polygon_layer) %>% 
  
  plot_3d(heightmap = delhi_mat, 
          windowsize = c(800,800), # c(800*wr,800*hr) 
          solid = FALSE, 
          zscale = 1,
          phi = 90, 
          zoom = .6, 
          theta = 0,
          shadowcolor = "grey50",  
          linewidth = 6,
          background = "white",
          solidlinecolor = "#013b39")

​

​

它应该是多角形线之上的橙色3D地图，但它没有工作，如我所预期的。

1. 我还试过使用Rayshder的泰勒网站示例https://www.tylermw.com/adding-open-street-map-data-to-rayshader-maps-in-r/

library(osmdata)

osm_bbox = c(extent(delhi_raster)[3],extent(delhi_raster)[1],extent(delhi_raster)[4],extent(delhi_raster)[2])
osm_bbox

raster_polygon_boundary <- osmdata::opq(osm_bbox) %>% 
  add_osm_feature("highway") %>%  # "admin_level" 
  osmdata_sf()

raster_polygon_boundary

输出：

Object of class 'osmdata' with:
                 $bbox : 76.8425681832661,28.4030759258059,77.347719586084,28.8793200072187
        $overpass_call : The call submitted to the overpass API
                 $meta : metadata including timestamp and version numbers
           $osm_points : 'sf' Simple Features Collection with 0 points
            $osm_lines : NULL
         $osm_polygons : 'sf' Simple Features Collection with 0 polygons
       $osm_multilines : NULL
    $osm_multipolygons : NULL

我得到了0多边形和线以上，所以我不能添加任何polygon之上的3D绘图。

我该怎么解决这个问题。感谢你的帮助。

Answer 1

将alphalayer添加到add_overlay(polygon_layer,alphalayer = .6)中是有帮助的，尽管它起了作用，但透明度仍然不能很好地工作。它在情节中造成了一些whiteness。如果其他人有更好的答案或改进方法，请随意分享。

delhi_mat %>%
  
  height_shade(texture = grDevices::colorRampPalette(c("#9a133d","orange","red","purple"
                                                       ))(256)) %>% 
  add_overlay(polygon_layer,alphalayer = .6) %>% 
  
  add_overlay(generate_label_overlay(delhi_district_shp, extent = extent(delhi_raster),
                                     text_size = 5, point_size = 1, 
                                     halo_color = "white",halo_expand = 5, 
                                     seed=1,
                                     heightmap = delhi_mat, data_label_column = "DISTRICT")) %>% 
  
  plot_3d(heightmap = delhi_mat, 
          windowsize = c(800,800), # c(800*wr,800*hr) 
          solid = FALSE, 
          zscale = .7,
          phi = 90, 
          zoom = .6, 
          theta = 0,
          shadowcolor = "grey50",  
          linewidth = 6,
          background = "white",
          solidlinecolor = "#013b39")

​

​