【808】R语言实现Hotspot Analysis

参考：Emerging Hot Spot Analysis（前半部分是static hotspot analysis）

参考：dplyr 说明文档

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代码：

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library (sfdep) library (dplyr)   # %>% is the same as |>   # guerry is a dataset from sfdep # mutate: Create, modify, and delete columns (keep all columns) # include_self: Includes self in neighbor list # st_contiguity: Identify polygon neighbors # st_weights: Calculate spatial weights   guerry_nb <- guerry %>%   mutate (     nb =  include_self ( st_contiguity (geometry)),     wt =  st_weights (nb)   )   # transmute: Create, modify, and delete columns (only keep new columns) # local_gstar_perm: Local G* # tidyr::unnest: one column -> many detailed columns (gi*, p score, etc.)   donat_gistar <- guerry_nb %>%   transmute (gi_star =  local_gstar_perm (donations, nb, wt, nsim = 199)) |>   tidyr:: unnest (gi_star)   # case_when: A general vectorised if # create a new column called cluster, which stores different categories of hotspot results   hotspot_results <- donat_gistar %>%   mutate (cluster =  case_when (     p_folded_sim > 0.1 ~  "Not Significant" ,     p_folded_sim <= 0.01 & gi_star < 0 ~  "Cold Spot - 99% Confidence" ,     p_folded_sim <= 0.01 & gi_star > 0 ~  "Hot Spot - 99% Confidence" ,     p_folded_sim <= 0.05 & gi_star < 0 ~  "Cold Spot - 95% Confidence" ,     p_folded_sim <= 0.05 & gi_star > 0 ~  "Hot Spot - 95% Confidence" ,     p_folded_sim <= 0.1 & gi_star < 0 ~  "Cold Spot - 90% Confidence" ,     p_folded_sim <= 0.1 & gi_star > 0 ~  "Hot Spot - 90% Confidence"   ))   # tm_shape: Specify the shape object # tm_polygons: Draw polygons # "cluster" is a column of hotspot_results   tm_shape (hotspot_results, name =  "Hotspot Detection" ) +   tm_polygons ( "cluster" , title =  "Hotspot Category" ,               palette =  c ( "Hot Spot - 99% Confidence" =  "#d62a24" ,                           "Hot Spot - 95% Confidence" =  "#ed7551" ,                           "Hot Spot - 90% Confidence" =  "#f6b985" ,                           "Not Significant" =  "#fcfebf" ,                           "Cold Spot - 90% Confidence" =  "#c0cdbe" ,                           "Cold Spot - 95% Confidence" =  "#859fba" ,                           "Cold Spot - 99% Confidence" =  "#4576b5" ),                          alpha = 0.7, lwd = 0.8)

效果：